Pennsylvania Underpayment of Estimated Tax By Individuals

Underpayment of Estimated Tax By Individuals
2023 Underpayment of Estimated Tax by Individuals (REV-1630)
2309710057
(EX) MOD (FI) 10-23

REV-1630

UNDERPAYMENT OF ESTIMATED TAX
BY INDIVIDUALS

START Name as shown on PA-40

2023

Social Security Number

➜
BEFORE YOU BEGIN: Did you qualify for 100 percent tax forgiveness in 2022? If yes, stop here. You do not owe an estimated underpayment penalty
and are not required to complete this form or include it with your return. If no, continue to see if you qualify for any of the exceptions.

SECTION I

CALCULATING THE UNDERPAYMENT

1a. 2023 Tax Liability from Line 12 of Form PA-40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1a.

1b. Multiply the amount on Line 1a by 0.90. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1b.

2. Add the amounts reported on Lines 13, 17, 21, 22, and 23 of Form PA-40. . . . . . . . . . . . . . . . .

2.

3. Subtract Line 2 from Line 1a. If result is less than $246, stop here. . . . . . . . . . . . . . . . . . . . . . .

3.

4. Subtract Line 2 from Line 1b. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.

ESTIMATED PAYMENT DUE DATES - Fiscal filers see instructions.

a
April 17, 2023
5. Divide Line 4 by the number of payments required for the
year (usually four). Enter the result in the appropriate
columns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6. Estimated tax paid including carryover credit from
previous tax year. See instructions. . . . . . . . . . . . . . . . . .

5.

7. Overpayment (from Line 10) from a previous period.
See instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7.

8. Add Lines 6 and 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9. Underpayment. Subtract Line 8 from Line 5. If Columns a
through d are all zero, stop here. No penalty is due. . . . .
10. Overpayment. Subtract Line 5 from Line 8. If Columns a
through d all show an overpayment, stop here.
No penalty is due. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION II

b
June 15, 2023

c
Sept. 15, 2023

d
Jan. 16, 2024

6.

8.
9.
10.

EXCEPTIONS TO INTEREST

You will not have to pay interest on the underpayment if the tax payments you made as shown in Section II, Line 11 were paid on time and the
amount shown on Section II, Line 11 is equal to or more than the amount in Section II, Line 12 or Line 13, for the same payment period. This
exception does not apply if you did not file a return for the prior year or if the prior year’s return was filed as a part-year resident.

EXCEPTION 1 WORKSHEET – Section II, Line 11 Calculation

a
April 17, 2023

b
June 15, 2023

c
Sept. 15, 2023

d
Jan. 16, 2024

A. Divide the amount reported in Section I, Line 2 by 4. Enter
the amount in each of the four columns. . . . . . . . . . . . . . . . .
B. Enter the estimated payments reported in Section I, Line 6. Enter
the payments under the installment period in which they were paid.
C. Add Lines A and B under each column. . . . . . . . . . . . . . . . . .
11. Enter the amounts listed on Exception 1 Worksheet,
Line C. For Column a this is the amount from Line C
above. For Column b add the amounts of Columns a and
b from Line C; for Column c add the amounts from
Columns a, b, and c; and for Column d add the amounts
from Columns a, b, c, and d. . . . . . . . . . . . . . . . . . . . . . . . . . .

11.

12. Exception 1 – Tax on 2022 income using 2023 tax rate.
See instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12.

If the amount on Line 11 is equal to or greater than Line 12, you do not owe penalty for that quarter and you should place an X in the applicable box on
Line 14a or 14b for that quarter.

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2309810055

REV-1630 (EX) MOD (FI) 10-23

Social Security Number

Name as shown on PA-40:

SECTION II

EXCEPTIONS TO INTEREST cont.

EXCEPTION 2 WORKSHEET – Use this worksheet if your income was earned unevenly throughout 2023 and your 2023 estimated tax payments, tax
withholdings and credits equal at least 90 percent of the tax on your taxable income for the periods.
EXCEPTION 2 WORKSHEET – Section II, Line 13 Calculation

01/01/23 - 03/31/23 01/01/23 - 05/31/23 01/01/23 - 08/31/23 01/01/23 - 12/31/23

A. Enter your actual taxable income for the period. . . . . . . . . . . .
B. Multiply Line A by 3.07 percent (0.0307). This is the tax due. .
13. Exception 2 - Tax on 2023 income over three, five, eight
and 12 month periods. Enter 90 percent of Exception 2
Line B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Enter 90%

Enter 90%

Enter 90%

Enter 90%

13.

If the amount on Line 11 is equal to or greater than Line 13, you do not owe penalty for that payment period and you should place an X in the applicable
box on Line 14a or 14b for that quarter.

SECTION III

CALCULATING INTEREST

COMPLETE LINES 15 THROUGH 16 IF NONE OF THE EXCEPTIONS APPLY.
(SEE THE INSTRUCTIONS AND THE EXAMPLE OF INTEREST CALCULATION.) DO NOT USE FEDERAL CALCULATIONS.

9. Enter the amounts from Section I, Line 9. . . . . . . . . . . . . . . .

9.

14a. Number of days after due date of estimated payment to and
including date of annual payment or Dec. 31, 2023,
whichever is earlier. If Dec. 31 is earlier, enter 258, 199, and
107 respectively. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14a.

14b. Number of days after due date of estimated payment to and
including date of annual payment or April 15, 2024,
whichever is earlier. If April 15 is earlier, enter 90. . . . . . . . . .

14b.

14c. Number of days after Dec. 31, 2023 to and including date of
annual payment or April 15, 2024, whichever is earlier. If
April 15 is earlier, enter 106 in each column. . . . . . . . . . . . . .

14c.

15a. Number of days on Line 14a times 0.000192 times
underpayment on Line 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15a.

15b. Number of days on Line 14b times 0.000219 times
underpayment on Line 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15b.

15c. Number of days on Line 14c times 0.000219 times
underpayment on Line 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15c.

$

$

$
$

$

$

$

16. Interest. Add amounts on Lines 15a, b, and c. Include on Line 27 of Form PA-40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16.

$

SPECIAL EXCEPTION INFORMATION
Please enter the following information to verify the correct application of the special exceptions rule:
A. Enter the amount of your 2022 PA Tax Liability (Line 12 from your 2022 PA-40 tax return), less the amounts from
Lines 13, 17, 22, and 23 from your 2022 PA-40 tax return. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B. Did you make estimated payments beginning in the period in which it became
Yes
No
known that your income not subject to tax exceeded $8,000?
If the amount for Line A is $246 or greater, or if you answer “No” to Line B, you do not qualify for the special exception. To be eligible for the special
exception, you must also make estimated payments beginning in the period in which it becomes known that income not subject to withholding will
exceed $8,000. See the instructions for “DETERMINING THE UNDERPAYMENT AMOUNT ON WHICH THE ADDITION OF INTEREST MAY BE
ASSESSED” on Page 4 for additional information.
Filing Tips
The department calculates the following using two decimal places:
• Line 1b and Lines 4 through 10 of Section I;
• Lines A, B, C and 11 of Exception 1 of Section II;
• Line 13 of Exception 2 of Section II; and
• Lines 14a through 16 of Section III

Rounding to whole dollars is utilized only on the following:
• Lines 1a, 2 and 3 of Section I;
• Line 12 of Exception 1 of Section II; and
• Lines A and B of Exception 2 of Section III.

FOR ADDITIONAL INFORMATION, PLEASE SEE THE “EXAMPLE OF INTEREST CALCULATION” ON THE LAST PAGE OF THE INSTRUCTIONS

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2023
Instructions for Form REV-1630

Underpayment of Estimated Tax by Individuals

REV-1630 IN (EX) MOD 10-23

GENERAL INFORMATION
The estimated underpayment penalty is an interest penalty
for the failure to make estimated tax payments or the failure
to make estimated tax payments in the correct amount. The
interest rate used to determine the penalty is based upon the
interest rate determined each year on the underpayment of
taxes. Under Pennsylvania personal income tax law, any
individual who reasonably expects annual income for the tax
year to exceed $8,000 in 2023, disregarding income subject
to PA withholding, must declare and pay estimated tax. The
income threshold for estimated payment requirements
increases to $9,500 in tax year 2024.
IMPORTANT: If you are a Pennsylvania resident
working in Indiana, Maryland, New Jersey, Ohio,
Virginia or West Virginia and your employer does not withhold
PA personal income tax, you are required to make estimated
payments.
With the passage of Act 85 of 2012, taxpayers who qualified
for 100 percent Tax Forgiveness in the previous tax year are
not subject to the estimated underpayment penalty in the
subsequent tax year. Taxpayers who qualified for less than
100 percent Tax Forgiveness may take into account the Tax
Forgiveness Credit in the calculation of Exception 1 in
determining if they are subject to the penalty. See the
instruction for Line 12.
FARMERS
There are special estimated tax payment rules that apply to
farmers. These rules apply to those who cultivate, operate or
manage a farm for profit or gain. A farm is a tract of land
devoted to agriculture, pasturage, stock raising or some allied
industry. It includes dairy, stock and poultry farms.
If you meet both of the following tests, you do not owe interest
for underpaying estimated tax:
1) Your gross income from farming for the taxable year is at
least 2/3 of your gross income from all sources for the
taxable year; and
2) You filed your tax return and paid the entire amount due
by March 1 of the following year, or you paid all of your
estimated tax by Jan. 16, 2024.
If you meet these tests, please complete REV-1630A,
Underpayment of Estimated Tax by Individual Farmers. If you
do not meet both tests, you are not considered a farmer for
PA tax purposes. Please complete this form to see if you
qualify for any other exceptions to the interest penalty.

PURPOSE OF FORM
Use this form to determine if you paid enough estimated tax
in each of the four payment periods (Section I). If you did not
pay enough tax in any payment period, then there is an
underpayment for that period and a corresponding interest
penalty imposed. Use this form to determine if any exceptions
to the interest penalty apply (Section II). If an exception does
not apply, use this form to calculate the interest due (Section
III). This form must be filed even if one of the exceptions
applies. A different exception may apply for each payment
period.
NOTE: If you are using this form to calculate penalty
on your 2023 return, enclose a copy of this form
(including applicable worksheet) with Form PA-40.
WHO MUST COMPLETE
Taxpayers who do not make the correct amount of estimated
payments or those who do not meet any of the exceptions to
the interest penalty and have an estimated underpayment
penalty may complete the form to determine the amount of
their estimated underpayment penalty. Taxpayers who meet
the qualifications for Exception 1 for one or more of the
estimated tax payment periods may complete the form to
calculate the penalty or to show why the penalty should not
be applied. Taxpayers who meet the qualifications for one or
more of the estimated tax payment periods under Exception
2 in Section II must complete the Exception 2 Worksheet to
show why the penalty should not be applied.
IMPORTANT: The department will use its computer
system to calculate the penalty based upon the tax
liability calculated by the department and the estimated tax
payments received and carryover credit applied for a taxpayer
for the tax year. The department will also determine any
exceptions to the penalty for any of the estimated tax payment
periods using Exception 1 when calculating the penalty. If a
taxpayer does not include the penalty or incorrectly calculates
the penalty, the department will send correspondence to a
taxpayer notifying them of the correct penalty and reduce the
refund amount or bill a taxpayer for the amount due.
WHO MUST PAY INTEREST FOR
UNDERPAYMENT OF ESTIMATED TAXES
If you did not pay any estimated tax or did not pay the correct
estimated tax by any due date or if you did not pay the entire
2023 estimated tax in one payment on or before April 17,
2023, you may be charged an interest penalty. This is true
even if you are due a refund when you file your PA income
tax return. Interest is calculated separately for each due date.
Therefore, you owe interest for an earlier payment due date,

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1

even if you paid enough tax later to make up for the
underpayment.

determine if you have an underpayment. If you have an
underpayment, the penalty is calculated on this amount.

WHEN INTEREST IS APPLIED
In general and unless you qualify for the farming exemption,
there is an underpayment if your 2023 prepayments were not:

Line 5. Divide Line 4 by 4 and enter the amount in each of
the four Columns a through d.

● 90 percent of the estimated tax due for the payment period;
or
● 100 percent of the estimated tax due for the payment
period calculated by multiplying the taxable income on Line
11 of 2022 Form PA-40 by 3.07 percent (0.0307). This
provision does not apply if you did not file a prior year’s
return or if you filed your prior year’s return as a part-year
resident.
CAUTION: You can only use your prior year’s tax
liability as a safe harbor if the rates for the prior year
and the current year are the same. If the tax rate changes,
use the prior year’s income multiplied by the current year’s
rate to calculate the safe harbor.
The total estimated tax and credits for tax year 2023 must be
equal to or greater than the 2022 tax year liability per
installment period.

FORM INSTRUCTIONS
IDENTIFICATION INFORMATION
Name
Enter the name of the taxpayer. If a jointly filed return, enter
the name of the primary taxpayer (name shown first on the
PA-40, Personal Income Tax Return).
Social Security Number
Enter the Social Security number (SSN) of the taxpayer.

LINE INSTRUCTIONS
SECTION I
CALCULATING THE UNDERPAYMENT
Line 1a. Insert the tax liability figure from Line 12 of your 2023
PA-40 tax return.
Line 1b. Calculate 90 percent of Line 1a by multiplying Line
1a by 0.90.
Line 2. The credits allowed to reduce the tax due are also
used to reduce your tax liability for this calculation. Add
together the following lines from Form PA-40: Line 13 (Total
PA Tax Withheld), Line 17 (Nonresident Tax Withheld), Line
21 (Tax Forgiveness Credit), Line 22 (Resident Credit), and
Line 23 (Total Other Credits). If Line 2 is more than Line 1b,
you do not owe a penalty and do not need to complete this
form.
Line 3. Subtract Line 2 from Line 1a. If the amount is $246 or
more, complete Lines 4 through 10. If less than $246, you did
not owe estimated income tax and do not have to complete
this form.
Line 4. Subtract Line 2 from Line 1b. This amount is used to
2

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Fiscal year filers. For Column a use the 15th day of the
fourth month of the tax year, for Column b use the 15th day
of the sixth month of the tax year, for Column c use the 15th
day of the ninth month of the tax year and for Column d use
the 15th day of the first month following the close of the tax
year.
Line 6. Line 6 represents the timely payments credited to your
account for each of the four payment due dates. If you made
a payment after the due date, do not include that amount on
Line 6. Each column will indicate a total of your estimated
payments for the period. To calculate the amounts to be
entered on Line 6, use the following steps and insert the total
result for each column in the appropriate column. Do not
include any credits from Line 2.
In Column a, enter the amount of 2023 estimated tax
payment(s) made on or before April 17 intended for the first
estimated tax payment due date. Include in your estimated
tax payments in Column a any overpayment of tax from your
prior year’s return that you elected to apply to this year’s tax.
In Column b, enter the amount of 2023 estimated payments
made on or before June 15 intended for the second estimated
tax payment due date. In Column c, enter the amount of 2023
estimated payments made after June 15 and on or before
Sept. 15. In Column d, enter the amount of 2023 estimated
payments made after Sept. 15 and on or before Jan. 16,
2024.
If you filed a final return and paid the total tax due by Jan. 31,
2024, enter the amount paid with your return as the fourth
installment.
IMPORTANT: Complete Lines 7 through 10 for one
payment period before you go to the next payment
period.
Line 7. If you have an overpayment on Line 10 for the prior
payment period, enter that amount. This does not apply to the
April 17th payment period (Column a).
Line 8. Add Lines 6 and 7 for each of the columns to
determine the total payments applied to the payment period.
This figure will be used to determine if you have an
underpayment.
Line 9. If Line 5 is greater than Line 8 for any column,
calculate the amount of the underpayment for the payment
period by subtracting Line 8 from Line 5. If Line 8 is greater
than Line 5 for any column, subtract Line 5 from Line 8 and
enter it in the appropriate column and on Line 7 of the next
payment period. If Line 5 is not greater than Line 8 for any of
the Columns a through d, enter zero on Line 9. If all Columns
9a through 9d are zero, stop here. You do not owe the interest
penalty. If there are overpayments but not in every quarter,
go to the applicable columns for Lines 14a and 14b and place
an X in each column where an overpayment exists.
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Line 10. Calculate the amount of the overpayment for the
payment period. Enter this amount on Line 7 of the next
payment period. If you have an overpayment in the Jan. 16th
payment period, do not carry it to any other space on the
form.
If Line 9 is zero for all payment periods, you do not owe
interest penalty. If you have an underpayment on Line 9 in
any payment period, continue on to Section II, Exception 1
Worksheet.
NOTE: If there are columns with underpayments, you
must complete the rest of this form.

SECTION II
EXCEPTIONS TO INTEREST
Line 11. Enter the result of Exception 1 Worksheet, Line C.
Line 12. Exception 1 applies if your 2023 estimated tax
payments and credits equal the tax that would have been due
on your 2022 income using the current rate. This exception
does not apply if you did not file a return for the prior year or
if the prior year’s return was filed as a part-year resident.
To calculate, multiply Pennsylvania taxable income from your
2022 return by 3.07 percent (0.0307). From this amount,
subtract the amount of the Tax Forgiveness Credit on Line 21
of your 2022 return and enter the amount in Column d. Enter
25 percent of the Column d amount in Column a, 50 percent
of the Column d amount in Column b and 75 percent of the
Column d amount in Column c. If the amount on Line 11 is
equal to or greater than the amount on Line 12 in any of the
columns, you do not owe interest for that payment period and
you should place an X in the applicable line 14a or 14b for
that payment period. If the amount on Line 11 is less than the
amount on Line 12 for any payment period, continue on to
exception 2 for those periods.

made during the year, use the number of days after the
estimated payment due date to and including the date of the
annual payment or Dec. 31, whichever is earlier. If Dec. 31 is
earlier, enter 258 in Column a, 199 in Column b, and 107 in
Column c. Fiscal filers adjust according to estimated payment
due dates.
Line 14b. If no estimated payment was made for the fourth
payment period, use the number of days after the estimated
payment due date to and including date of annual payment
or April 15, 2024, whichever is earlier. If April 15 is earlier,
enter 90 in Column d. Fiscal filers adjust according to due
date of annual return.
Line 14c. Applies to first, second and third payment periods
for calendar year filers and any fiscal filer payments that were
due after Dec. 31. If no estimated payments were made, use
the number of days after Dec. 31, 2023 to and including date
of annual payment or April 15, 2024, whichever is earlier. If
April 15 is earlier, enter 106 in each column. Fiscal filers
adjust according to due date of the annual return.
If a taxpayer fully pays an underpayment after a required due
date but prior to or on the next due date, then the number of
days after due date of estimated payment in Lines 14a, 14b,
or 14c must be adjusted. To make the adjustment, count the
days from the due date to the date of payment.
If the taxpayer partially pays an underpayment after a
required due date but prior to or on the next due date, that
partial payment is considered a reduction, on the payment
date, to the oldest payment period’s underpayment. For such
situation, the taxpayer will need to adjust this part accordingly.
EXAMPLE OF WHEN ESTIMATED
UNDERPAYMENT APPLIES:
Tax liability for current tax year
Less current tax year’s
withholding and credits

$3,599
– 1,344
$2,255

Line 13. Exception 2 applies if your 2023 estimated tax
payments and credits equal at least 90 percent of the tax on
your actual taxable income for the periods from Jan. 1 to
March 31; Jan. 1 to May 31; Jan. 1 to August 31; and Jan. 1
to Dec. 31. Enter 90 percent of Exception 2 Worksheet, Line
B. If Line 11 is equal to or greater than Line 13, the exception
applies for that payment period and you should place an X in
the applicable line 14a or 14b for that payment period.

Current withholding and credits must be less than the smaller
of the following to be penalized for estimated under-payment:

SECTION III

Since the current PA tax liability minus current withholding and
credits is at least $246, and since the current year withholding
and allowable credits are less than $3,239, the taxpayer
should fill out Form REV-1630 to determine if there is an
underpayment of estimated tax. Please see the department’s
website for additional examples of when the underpayment
of estimated tax penalty is applicable and when the
exceptions apply.

CALCULATING INTEREST
Use this part of the form to calculate the amount of the interest
penalty due. If one of the exceptions applies for any of the
periods, place an X in the boxes under the column for that
period. You only have to complete Lines 14 and 15 for the
periods in which interest is due. The underpayment is the
amount on Line 9 for the appropriate payment period.
LINES 14a, 14b AND 14c.
Line 14a. Applies to first, second and third payment periods
for calendar year filers and any fiscal filer payments that were
due on or before Dec. 31. If no estimated payments were

• $3,239 (90 percent of the tax liability on the current return);
or
• $3,502 (PA taxable income on prior year’s return multiplied
by the current year’s tax rate).
In this case, $1,344 is less than both safe harbors.

DETERMINING IF THERE IS AN UNDERPAYMENT
AND HOW THE DEPARTMENT DETERMINES
THE DECLARATION
A taxpayer makes an underpayment of quarterly estimated
tax liability whenever he fails to declare and pay all or any

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part of the amount declared as the quarterly estimated
payment on a timely basis.
DETERMINING THE UNDERPAYMENT AMOUNT
UPON WHICH THE ADDITION OF INTEREST
MAY BE ASSESSED
The amount to be considered is that the taxpayer should have
paid in estimated taxes if the taxpayer could have used the
PA Tax Liability (Line 12) as shown on his PA-40 tax return.
The underpayment is the difference between the tax liability
times 90 percent, minus any credits for the applicable
payment period (calculated by dividing 90 percent of line 12
of Form PA-40 minus any withholding and credits, by the
number of estimated payment periods) and the estimated
payments paid on time for that payment period.
IMPORTANT: The amounts calculated in each of the
columns on Lines 12 and 13 for Exceptions 1 and 2
cannot be used to determine the underpayment penalty. You
must use Line 9 in this calculation. However, if you had no
estimated tax payment requirements for a previous tax year
due to the tax liability being below the threshold required for
estimated tax payments to be made, or because you were
eligible for 100 percent Tax Forgiveness, special exceptions
apply and you may not owe penalties for the payment periods
prior to meeting the estimated payment requirements.
Special exceptions only apply if a taxpayer files an original or
amended PA-40 ES (I), Declaration of Estimated or Estimated
Withholding Income, and makes the full estimated tax
payment due in the first period in which it is determined the
estimated payment requirements were met for a year
following a year in which no estimated payments were due or
required to be made.
If the PA-40 ES is not filed in the correct payment period, or
if the full amount of the estimated tax payment is not made
in that period, the special exception does not apply for any
payment periods, and the estimated underpayment penalty
will apply for all payment periods in which the estimated tax
underpayment exists.

In situations where conditions exist for the exception to apply,
complete the Exception 2 worksheet to indicate the quarters
in which the income (Line A) was earned and the tax liability
(Line B) for those periods. Place an X in the applicable box
on Line 14a to indicate that you do not owe a penalty for each
payment period the special exception applies. You must also
complete the “Special Exception Information” section in
Section III by entering the information requested for Lines A
and B.
BILLING THE ADDITION OF INTEREST
The interest to be added to the taxpayer’s tax liability for an
underpayment is to be billed per quarter. The interest to be
added is based upon the amount of the underpayment per
payment period.
Interest is assessed upon the under-payment amount until
the taxpayer has made payments for the applicable payment
period that equal the amount of the declared estimated
payment liability. However, interest may not be imposed
beyond the due date of the taxpayer’s taxable year (typically
April 15th) for any quarter.
If a taxpayer makes a late payment for a payment period in
which an under-payment exists and his total payments for that
period are less than the amount of the declared estimated tax
liability or the required estimated amount, interest is billed
upon the underpayment amount. However, as soon as a
taxpayer makes a late payment for a payment period in which
an underpayment exists, the underpayment is reduced by the
late payment amount even if the total payment amount is less
than the amount of the taxpayer’s declared estimated tax
liability.
When the taxpayer has made payments for the
underpayment period equal to his declared estimated tax
liability, the department does not impose interest for that
payment period.

EXAMPLE OF INTEREST CALCULATION
1st Estimated Payment 2nd Estimated Payment 3rd Estimated Payment 4th Estimated Payment
Due Date
Due Date
Due Date
Due Date
9. Underpayment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
14a. Days late through 12/31/23 (1st, 2nd, and 3rd estimated
payment due dates) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14a.

14b. Days late 01/16/24 through 04/15/24 (4th estimated
payment due date) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14b.

14c. Days late 01/01/24 to 04/15/24 (1st, 2nd and 3rd estimated
payment due dates) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14c.
15a. Days on Line 14a times 0.000192 (2023 daily interest rate)
times underpayment of $473.75 . . . . . . . . . . . . . . . . . . .

15a.

15b. Days on Line 14b times 0.000219 (2024 daily interest rate)
times underpayment of $473.75 . . . . . . . . . . . . . . . . . . .

15b.

15c. Days on Line 14c times 0.000219 (2024 daily interest rate)
times underpayment of $473.75 . . . . . . . . . . . . . . . . . . .

15c.

$473.75

$473.75

$473.75

258

199

107
90

106

106

106

$23.47

$18.10

$9.73
$9.44

$11.00

$11.00

$11.00

16. Total Lines 15a, 15b, and 15c to determine penalty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

REV-1630

GO DIRECTLY TO FORM

$473.75

16.

$93.74

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