North Dakota calendar and forms

North Dakota keeps its calendar locked to the federal one. Form ND-1 is due the same day as the Form 1040, April 15, 2027; the four estimated payments fall on the federal dates; and a federal extension carries over to the state return automatically, to October 15, 2027, with no state form to file. The thing to remember about the extension is that it is an extension of time to file and not to pay: the Office of State Tax Commissioner charges 12% a year interest from April 15 on any tax paid with an extended return, and a prepayment with Form ND-1EXT by April 15 is the only way to avoid it.

The form side is simple. There is one full return, Form ND-1, and a one-page short return, Form ND-EZ, for full-year residents with nothing to add, subtract or claim. Because the return starts from federal taxable income, most North Dakota filers touch the return and nothing else; the schedules attach only when something applies, and the common ones are the nonresident and part-year schedule for people who moved, the credit for tax paid to another state, and the estimated tax form.

The 2027 filing season, dated

How the extension really works

If you have a federal extension, you have a North Dakota extension. The 2025 Form ND-1 booklet says the Department automatically recognizes a federal extension; there is no state form to file, but you must fill in the Extension circle in Section E of Form ND-1 (Section D of ND-EZ) so the return is not treated as late. Someone who needs a North Dakota extension without a federal one files Form 101 by the April 15 due date, with good cause shown; that one is not automatic.

What neither extension does is stop interest. The booklet calls it extension interest: 12% a year from April 15 to the date the return is filed or the extended due date, whichever is first, on the tax paid with the return. There is no late-filing penalty as long as the return is filed and the tax paid by the extended date, so the extension is worth having; it just costs 1% a month on the balance. The way around it is Form ND-1EXT, the extension payment voucher, mailed with a check by April 15 or replaced by an electronic payment at tax.nd.gov by the same date. A prepayment on ND-1EXT is claimed on Form ND-1 line 27, and anyone who makes one must file ND-1 rather than ND-EZ.

Estimated payments

North Dakota requires estimated payments only when four things are all true, and the Form ND-1ES instructions list them: you are required to make federal estimated payments; your 2025 North Dakota net tax was $1,000 or more; you expect to owe $1,000 or more for 2026 after withholding; and your withholding is less than both 90% of this year’s tax (66⅔% for a qualified farmer) and 100% of last year’s. The 100%-of-last-year test does not apply to someone who moved into North Dakota during 2025 with no North Dakota income before the move. There is no higher safe-harbor tier for high incomes.

Each installment is a quarter of the year’s estimate, due April 15, June 15, September 15 and January 15. Underpayment interest is 12% a year from each installment date, figured on Schedule ND-1UT, which is only completed by people who were required to pay federal estimates. Because the 0% bracket keeps so many state bills under $1,000, plenty of North Dakota filers who pay federal estimates owe none to the state; the ones who do are usually the self-employed, owners of pass-through businesses, and anyone with a large capital gain, a Roth conversion or an inherited IRA distribution that had no state withholding.

The forms, in the order a filer meets them

Filing, paying and checking a refund

North Dakota is in the IRS federal/state modernized e-file program, so any commercial software that files the Form 1040 files Form ND-1 with it, and the Department charges nothing for electronic filing. Free File is available through the IRS program’s vendors, each with its own income and age limits; the Department’s e-file page says to check eligibility through the ND Free File tool on ND TAP, the state’s Taxpayer Access Point at tap.tax.nd.gov, and warns that the add-ons the vendors offer are where the charges come from. The Department does not run a state-only filing program of its own, and North Dakota was not a Direct File state.

Payments go through ND TAP as well, at tax.nd.gov/payment, by electronic check or by debit or credit card, and can be scheduled when the return is e-filed. The Department’s individual page says refund processing is anticipated to take about 30 days. Where’s My Refund, also on ND TAP, needs the tax year, Social Security number, filing status and the exact refund amount from line 32 of ND-1 or line 6 of ND-EZ. If a bank rejects a direct deposit, the Department mails a check to the address on the return, and North Dakota participates in refund offset, so a refund can be taken for a debt to a state or federal agency; the notice names the agency. Last year’s refund, if it was deducted federally, is reported on Form 1099-G, which the Department mails only in some cases and otherwise provides through a lookup tool on its website.

Paper returns go to the Office of State Tax Commissioner, P.O. Box 5621, Bismarck, ND 58506-5621, with Form ND-1PRV if a check is enclosed. The Department’s main number is 701-328-7088 and the individual income tax section’s email is individualtax@nd.gov; the office is at 600 E. Boulevard Ave., Dept. 127, Bismarck, ND 58505-0599. Help with the Primary Residence Credit application is at 701-328-7988 or 1-877-649-0112.