Montana State Tax Extension
Montana Personal Tax ExtensionForm IT
Skip the wait – eFile your Federal and Montana state return through our secure platform with step-by-step guidance and 24/7 support.
File Your Tax Return Now →Montana’s Automatic Personal Income Tax Extension – 90% or Prior-Year Safe Harbor
Montana grants every taxpayer an automatic six-month extension for filing personal income tax returns – no form, no federal extension, and no state approval needed. The Montana Department of Revenue automatically extends the filing deadline from April 15, 2026, to October 15, 2026. To avoid late-payment penalties, taxpayers must meet one of Montana’s two payment thresholds by April 15.
Pay 90% of Current Year – or 100% of Prior Year
By April 15, pay either 90% of your current year’s Montana tax liability or 100% of the prior year’s tax – whichever results in a lower payment. Either qualifies as full safe-harbor protection.
Filing Penalty Capped at $50 or Tax Due
Montana’s failure-to-file penalty is the lesser of $50 or the actual tax due – among the most modest penalties in the country. Still, filing on time by October 15 is always the right call.
Montana’s Safe Harbor Payment Rules
Montana offers two safe harbors for avoiding late-payment penalties under an extension. Pay at least 90% of your current year’s Montana tax liability by April 15, 2026 – or 100% of what you owed for the prior tax year, whichever is lower. Choose the option that works in your favor. Any remaining balance is due when you file by October 15.
Using Form IT
For mail-in payments, use Form IT (Montana Individual Income Tax Payment Voucher). If paying online through Montana’s TAP (TransAction Portal), no form is required – though note that card payments through TAP carry a fee.
Late Filing and Payment Penalties
Montana’s failure-to-file penalty is the lesser of $50 or the amount of tax due – one of the most favorable in the country for small balances. The failure-to-pay penalty is 1.2% of unpaid tax per month, capped at 12%. Meeting the safe harbor payment by April 15 eliminates the payment penalty entirely.
Best Practices
- ✓No form or federal extension required – Montana’s extension is completely automatic.
- ✓By April 15, 2026, pay either 90% of current year tax or 100% of prior year tax – whichever is less.
- ✓Use TAP at tap.dor.mt.gov for online payment (ACH available; card payments have a fee).
- ✓File your completed Montana return by October 15, 2026.
Montana’s extension is clean and uncomplicated – automatic, no paperwork, and with a generous dual safe harbor for payment. Choose whichever threshold is lower, pay by April 15, and file by October 15, 2026.
Quick Reference Table
| Item | Details |
|---|---|
| State Abbreviation | MT |
| Extension Status | Approved Automatically |
| Return Due Date | April 15, 2026 |
| Extended Due Date | October 15, 2026 |
| Online Payment | Montana | Online Tax Extension Payment |
| Payment Voucher | Form IT | Montana Individual Income Tax Payment Voucher |
| State Payment Agency | Montana Department of Revenue |
| Failure to File Penalty | Lesser of $50 or the amount of tax due |
| Failure to Pay Penalty | 1.2% of unpaid tax per month, up to 12% |
Extended? Your Montana Return Deadline Is Coming Up.
File your Montana return securely online – accurate, fast, and backed by 24/7 support. Most filers finish in minutes.
File My Return Securely →Montana Extension Payment Options
Pay 90% of your current year Montana tax (or 100% of prior year’s) by April 15, 2026. TAP (TransAction Portal) at tap.dor.mt.gov handles both ACH and card payments.
Pay via TAP
Visit tap.dor.mt.gov for direct bank debit. ACH payment option available. Confirmation is immediate.
Pay by Card – Fee Applies
Also available at tap.dor.mt.gov. A fee applies when paying with a credit or debit card through the TAP portal.
Mailing Address with Payment
P.O. Box 6309
Helena, MT 59604-6309
Social Media
