Purpose of form Use this form to calculate and pay estimated North Dakota individual income tax. Individuals generally must pay their income tax in one of two ways—through the withholding of income tax from their paychecks or through the payment of estimated tax. If you receive earnings from self- employment, interest, dividends, rents, and other types of income not subject to withholding, you may have to pay estimated tax. Who must pay estimated tax? You must pay estimated North Dakota income tax for the 2026 tax year if all four of the following conditions apply: 1. You are required to pay estimated federal income tax for the 2026 tax year. This condition applies whether or not you actually make the required payment of estimated tax to the Internal Revenue Service. 2. Your net tax liability for the 2025 tax year was equal to or more than $1,000.

Note: If you were not required to file a North Dakota income tax return for the 2025 tax year, your net tax liability for 2025 is zero for this purpose. 3. You expect to owe (after subtracting your estimated North Dakota income tax withholding) an amount equal to or more than $1,000 for the 2026 tax year. 4. You expect your estimated North Dakota income tax withholding for the 2026 tax year to be less than the smaller of:

a. 90% of your net tax liability for the 2026 tax year.

Note: Substitute 66 2/3% if a qualified farmer. See “Farmer” under “Payment amounts and due dates” later in these instructions.

b. 100% of your net tax liability for the 2025 tax year.

Note: If you moved into North Dakota during 2025 and had no income from North Dakota prior to the move, part b does not apply; you must satisfy the 90% threshold in part a. How to determine your estimated tax Complete the worksheet on page 2 to determine if you have to pay estimated tax for 2026. For line 1 of the worksheet, estimate your federal taxable income using the 2026 Form 1040-ES, the federal estimated tax form for individuals. For lines 2, 4 and 7 of the worksheet, see the instructions to the 2025 Form ND-1 and 2025 Schedule ND-1TC. Married persons filing separate returns. If you are married and plan to file separate federal and North Dakota income tax returns for the 2026 tax year, you and your spouse must make separate estimated tax payments based on your separate incomes. Each of you should obtain and complete Form ND-1ES to determine your separate estimated tax payments. Payment amounts and due dates In general, one-fourth (25%) of the total estimated tax that you are required to pay (from line 14 of the worksheet) must be paid by each of the following due dates:  1st installment April 15, 2026  2nd installment June 15, 2026  3rd installment September 15, 2026  4th installment January 15, 2027 The above due dates apply if your tax year is a calendar year—January 1 through December 31, 2026. However, if you file on a fiscal year basis, the installments are due on the 15th day of the 4th, 6th, and 9th months of the current tax year, and the 15th day of the 1st month of the following tax year. If any installment due date falls on a Saturday, Sunday, or legal holiday, the installment is not due until the next business day. Farmer. If you qualify as a farmer for federal estimated income tax purposes for the 2026 tax year, you may pay your estimated tax according to the general rules explained above, or you may pay the full amount of your estimated tax due by January 15, 2027. Note: Regardless of the option chosen, you have until the regular due date (generally, April 15, 2027) to file your 2026 North Dakota individual income tax return. Note: The tax calculation in the worksheet (on page 2) does not take into account the 3­‑year elected farm income averaging on Schedule ND-1FA. Part-year requirement. If you are a full-year nonresident or you changed your residence to North Dakota during the 2026 tax year, and you do not receive income from North Dakota sources until after the first installment due date (generally, April 15, 2026), you must pay the required estimated tax in equal payments over the remaining installment due dates following the receipt of income from North Dakota sources. How and where to pay Electronic payment. Instead of paying by check or money order with a payment voucher, the payment may be made online with an electronic check or a debit or credit card. To make an electronic payment, go to www.tax.nd.gov and select “Make A Payment.” If paying electronically, do not use the payment vouchers attached to this form. Payment by check or money order. If you choose to pay by check or money order, make it payable to “ND State Tax Commissioner.” To ensure proper credit to your account, write the last four digits of your social security number and “2026 ND-1ES” on your check or money order. Detach and complete the applicable installment’s payment voucher. Mail your payment and voucher to:

Office of State Tax Commissioner

PO Box 5622

Bismarck, ND 58506-5622 A check must be drawn on a U.S. or Canadian bank, be in U.S. dollars, and use a standard 9-digit routing number. A check drawn on a foreign bank (except one in Canada) cannot be accepted. Underpayment or late payment interest Interest may be charged if you do not pay enough estimated tax, or if you do not make the payment on time or in the required amount. This applies even if you have a refund on your 2026 North Dakota individual income tax return. Interest is calculated at the rate of 12% per year from the installment due date to the earlier of the date the estimated tax is paid or the regular due date of the return (generally, April 15, 2027). Need help? If you have questions or need forms, see page 3 of this form for how to contact us. Privacy Act Notification. In compliance with the Privacy Act of 1974, disclosure of a social security number or Federal Employer Identification Number (FEIN) on this form is required under N.D.C.C. §§ 57-01-15 and 57-38-62, and will be used for tax reporting, identification, and administration of North Dakota tax laws. Disclosure is mandatory. Failure to provide the social security number or FEIN may delay or prevent the processing of this form. ESTIMATED INCOME TAX - INDIVIDUALS OFFICE OF STATE TAX COMMISSIONER SFN 28709 (12-2025) Form ND-1ES 2026

2026 estimated income tax worksheet—individuals 1. Estimated federal taxable income for the 2026 tax year (from worksheet in 2026 Federal

Form 1040-ES)....................................................................................................................... 1 ________________ 2. Addition adjustments—see the 2025 Form ND-1 instruction booklet (lines 2 through 3)

for addition adjustments........................................................................................................... 2 ________________ 3. Balance (Add lines 1 and 2)...................................................................................................... 3 ________________ 4. Subtraction adjustments—see the 2025 Form ND-1 instruction booklet (lines 5 through 16)

for subtraction adjustments...................................................................................................... 4 ________________ 5. North Dakota taxable income (Subtract line 4 from line 3)............................................................ 5 ________________ 6. North Dakota income tax—calculate the tax for the amount on line 5 as follows............................... 6 ________________

• If you (and your spouse, if filing jointly) were full-year residents, calculate the tax using

the applicable 2026 Tax Rate Schedule below.

• If you (or your spouse, if filing jointly) was a full-year nonresident or a part-year resident,

complete lines 15 through 19 below. 7. Credits—see the 2025 Form ND-1 instruction booklet (lines 21 through 23) for allowable credits 7 ________________ 8. Net tax liability (Subtract line 7 from line 6)................................................................................ 8 ________________ 9. Estimated North Dakota income tax withholding for the 2026 tax year............................................ 9 ________________ 10. Balance due (Subtract line 9 from line 8). If the amount on this line is less than $1,000,

stop here; you do not have to pay estimated tax......................................................................... 10 ________________ 11. Multiply line 8 by 90% (.90) [or 66 2/3% (.6667) if a qualified farmer]........ 11 ________________ 12. Net tax liability from 2025 Form ND-1, line 25. If you were not required

to file a 2025 return, enter 0. If the amount on this line is less than

$1,000, stop here; you do not have to pay estimated tax........................... 12 ________________ 13. Enter the smaller of line 11 or line 12. However, if you moved into North Dakota during the

2025 tax year and had no income from North Dakota prior to the move, enter the amount

from line 11. If line 9 is equal to or greater than the amount on this line, stop here;

you do not have to pay estimated tax........................................................................................ 13 ________________ 14. Minimum annual payment (Subtract line 9 from line 13). Divide this amount by 4 to determine

the amount to pay on each installment due date. See “Payment amounts and due dates” in

the instructions on page 1 for the due dates and for exceptions to paying in four installments........... 14 ________________ Full-year nonresident or part-year resident tax calculation only (lines 15 through 19) 15. Calculate the tax for the amount on line 5 using the applicable 2026 Tax Rate Schedule below........... 15 ________________ 16. Income from North Dakota sources. Enter the portion of your estimated

federal adjusted gross income that is reportable to North Dakota

(reduced by amount from line 4 above).................................................... 16 ________________ 17. Estimated federal adjusted gross income (reduced by U.S.

obligation interest)................................................................................ 17 ________________ 18. North Dakota income ratio (Divide line 16 by line 17. Round to nearest two decimal places.

If line 16 is more than line 17, enter 1.00).................................................................................. 18 ________________ 19. Multiply line 15 by line 18. Enter this amount on line 6 above........................................................ 19 ________________ 2026 Forms ND-1 and ND-EZ Tax Rate Schedules

Single Married filing jointly and Qualifying surviving spouse

If North Dakota

If North Dakota

taxable income is:

taxable income is:

Over But not over Your tax is: Over But not over Your tax is:

$ 0 $ 49,575 $...... 0.00 + 0.00% of North Dakota taxable income $ 0 $ 82,800 $...... 0.00 + 0.00% of North Dakota taxable income

49,575 250,400.......... 0.00 + 1.95% of amount over $ 49,575 82,800 304,850........... 0.00 + 1.95% of amount over $ 82,800

250,400.....................3,916.09 + 2.50% of amount over 250,400 304,850....................... 4,329.98 + 2.50% of amount over 304,850 Married filing separately

Head of household

If North Dakota

If North Dakota

taxable income is:

taxable income is:

Over But not over Your tax is: Over But not over Your tax is:

$ 0 $ 41,400 $...... 0.00 + 0.00% of North Dakota taxable income $ 0 $ 66,400 $...... 0.00 + 0.00% of North Dakota taxable income

41,400 152,425.. $...... 0.00 + 1.95% of amount over $ 41,400 66,400 277,600........... 0.00 + 1.95% of amount over $ 66,400

152,425 ...................2,164.99 + 2.50% of amount over 152,425 277,600....................... 4,118.40 + 2.50% of amount over 277,600 2026 Form ND-1ES SFN 28709 (12-2025), Page 2

Call Questions: 701-328-1247 Forms: 701-328-1243 If speech or hearing impaired, call us through Relay North Dakota at 1-800-366-6888. Email Request forms, ask questions, or send messages to us via e­mail at individualtax@nd.gov Website tax.nd.gov Write Office of State Tax Commissioner 600 E. Boulevard Ave., Dept. 127 Bismarck, ND 58505-0599 Walk-in assistance Stop in to see us in person at our main office in Bismarck. State Capitol, 8th Floor Monday through Friday (except holidays) 8:00 a.m. to 5:00 p.m. Record of estimated tax payments for 2026 tax year Installment number Payment due date 1 Date Paid Check or money order number Amount paid Amount, if any, applied from 2025 return 2 Total amount paid 1 April 15, 2026 2 June 15, 2026 3 Sept. 15, 2026 4 Jan. 15, 2027 Total estimated tax paid for 2026................................................................................................... 1 In the case of (1) a fiscal year filer, (2) a farmer, or (3) an individual whose estimated tax requirement does not begin until after April 15, 2026, see instructions for applicable due dates. 2 If you attached a statement to your 2025 North Dakota return electing to apply part or all of your 2025 overpayment to a quarter other than the first quarter of 2026, enter the overpayment on the applicable quarter’s line. 2026 Form ND-1ES SFN 28709 (12-2025), Page 3 Mail payment and voucher to: Office of State Tax Commissioner PO Box 5622 Bismarck, ND 58506-5622 IIT City, State, ZIP Code Mailing Address Name Social Security Number . . . . . . . . . . . . .► Spouse's Name Do not use this voucher if paying electronically 2026 Payment Voucher 1 焁Due April 15, 2026 Spouse's Social Security Number . . . . . ► FORM ND-1ES INDIVIDUAL ESTIMATED TAX PAYMENT VOUCHER North Dakota Office of State Tax Commissioner SFN 28709 (12-2025) Payment Amount ►$ Write last four digits of Social Security Number and "2026 ND-1ES" on check • Make payable to: ND State Tax Commissioner •

 Detach here and mail with payment  Mail payment and voucher to: Office of State Tax Commissioner PO Box 5622 Bismarck, ND 58506-5622 IIT City, State, ZIP Code Mailing Address Name Social Security Number . . . . . . . . . . . . .► Spouse's Name Do not use this voucher if paying electronically 2026 Payment Voucher 2 焁Due June 15, 2026 Spouse's Social Security Number . . . . . ► FORM ND-1ES INDIVIDUAL ESTIMATED TAX PAYMENT VOUCHER North Dakota Office of State Tax Commissioner SFN 28709 (12-2025) Payment Amount ►$ Write last four digits of Social Security Number and "2026 ND-1ES" on check • Make payable to: ND State Tax Commissioner •

 Detach here and mail with payment  Mail payment and voucher to: Office of State Tax Commissioner PO Box 5622 Bismarck, ND 58506-5622 IIT City, State, ZIP Code Mailing Address Name Social Security Number . . . . . . . . . . . . .► Spouse's Name Do not use this voucher if paying electronically 2026 Payment Voucher 3 焁Due September 15, 2026 Spouse's Social Security Number . . . . . ► FORM ND-1ES INDIVIDUAL ESTIMATED TAX PAYMENT VOUCHER North Dakota Office of State Tax Commissioner SFN 28709 (12-2025) Payment Amount ►$ Write last four digits of Social Security Number and "2026 ND-1ES" on check • Make payable to: ND State Tax Commissioner •

 Detach here and mail with payment  Mail payment and voucher to: Office of State Tax Commissioner PO Box 5622 Bismarck, ND 58506-5622 IIT City, State, ZIP Code Mailing Address Name Social Security Number . . . . . . . . . . . . .► Spouse's Name Do not use this voucher if paying electronically 2026 Payment Voucher 4 焁Due January 15, 2027 Spouse's Social Security Number . . . . . ► FORM ND-1ES INDIVIDUAL ESTIMATED TAX PAYMENT VOUCHER North Dakota Office of State Tax Commissioner SFN 28709 (12-2025) Payment Amount ►$ Write last four digits of Social Security Number and "2026 ND-1ES" on check • Make payable to: ND State Tax Commissioner •