North Dakota (ND)
April 15, 2026
October 15, 2026
✓ Automatic w/ Federal
ND — North DakotaNorth Dakota Personal Income Tax Extension — What You Need to Do
If you have a federal extension (Form 4868), North Dakota automatically extends your filing deadline to October 15, 2026 — no separate North Dakota form needed, just check the extension box when you file. You only need Form ND-1EXT if you’re prepaying by paper check, or Form 101 if you didn’t get a federal extension.
North Dakota Extension Checklist — 2026
Two things to handle. Whether you need a form at all depends on your federal extension status and how you’re paying.
April 15, 2026
Pay Any North Dakota Tax Due (File Form ND-1EXT If Paying by Check)
Check with Form ND-1EXT ND Office of State Tax Commissioner
PO Box 5622
Bismarck, ND 58506-5622
An extension doesn’t extend the time to pay — interest still accrues.
October 15, 2026
File Federal + North Dakota Return
File your federal return now and add your North Dakota state return — Form ND-1 — in the same session. Filing sooner means a faster refund. Your North Dakota extended deadline is October 15.
Start Federal + North Dakota Return →
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North Dakota Late Filing & Payment Penalties — What It Costs to Wait
North Dakota charges the same penalty structure for late filing and late payment, plus a higher interest rate specifically during the extension period.
| Charge Type | Rate | Cap | Trigger |
|---|---|---|---|
| Failure to File / Failure to Pay | 5% of unpaid tax (or $5, whichever is greater) for the first month, plus 5% per additional month | 25% | Return filed and/or tax paid after the due date |
| Interest (during valid extension) | 12% per year from the original due date | No cap | Any unpaid tax while filing under a valid extension |
| Interest (general, post-due-date) | 1% per month or part of a month | No cap | Any unpaid tax remaining after the due date — cannot be waived |
North Dakota State Extension Details
| Extension Type | Automatic with Federal Extension |
| Original Filing Deadline | April 15, 2026 |
| Extended Filing Deadline | October 15, 2026 |
| Extension Period | 6 months (federal-aligned) |
| Extension Form | Form ND-1EXT (payment voucher only) or Form 101 (only if no federal extension) |
| Return Form | Form ND-1 |
| Federal Extension Required? | Not required, but a federal extension automatically covers North Dakota through October 15 with no ND form needed |
| Payment Deadline | April 15, 2026 (extension does not extend time to pay) |
| Online Payment Portal | ND Taxpayer Access Point (TAP) |
| Form ND-1EXT Mailing Address | Office of State Tax Commissioner, PO Box 5622, Bismarck, ND 58506-5622 |
| Return Mailing Address (refund or balance due) | Office of State Tax Commissioner, PO Box 5621, Bismarck, ND 58506-5621 |
| State Agency | North Dakota Office of State Tax Commissioner |
| Failure to File/Pay Penalty & Interest | 5% first month + 5%/additional month (cap 25%); 12% annual interest during extension, 1%/month otherwise |
North Dakota Tax Extension — Frequently Asked Questions
Do I need to file any form to get North Dakota’s extension?
No — if you have a valid federal extension, North Dakota automatically extends your deadline to October 15, 2026. Just check the extension box on Form ND-1 when you eventually file. No ND form is required merely to obtain the extension.
What is Form ND-1EXT for, then?
It’s a prepayment voucher, used only if you owe North Dakota tax and want to pay by paper check or money order. If you’re paying electronically through TAP, you don’t need it.
What if I didn’t get a federal extension?
You can request a North Dakota-specific extension using Form 101, which requires showing “good cause” and must be postmarked by April 15, 2026.
Why is the interest rate on the penalty table higher than 1% per month?
North Dakota applies a separate, higher 12%-per-year interest rate specifically to unpaid tax during a valid extension period — distinct from the general 1%-per-month rate that applies to unpaid tax outside of an extension.
Which North Dakota return form do I need?
Form ND-1 is North Dakota’s standard individual income tax return; a simplified ND-EZ may be available for qualifying filers.
Where do I mail my return versus my extension payment?
Form ND-1EXT prepayments go to PO Box 5622. Completed ND-1 returns — whether refund or balance due — go to PO Box 5621 instead. Different addresses, so double-check before mailing.
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