Idaho State Tax Commission

Tax Commission News Release

Need an extension to file your Idaho income tax return?

BOISE, IDAHO — May 13, 2021 — If you can’t file your 2020 Idaho income tax return by the May 17 deadline, you can get an automatic extension if you pay enough of your total tax due by May 17.

To qualify, you need to pay:

  • 80% of the estimated tax you owe for 2020, or 
  • 100% of the total tax reported on your 2019 income tax return

An automatic extension means you don’t have to file a written request. But an extension of time to file your return isn’t an extension of time to pay your tax. With a valid extension, you can avoid a penalty for filing late, but you’ll owe 2% annual interest on the remaining tax until it’s paid.

To see if you qualify, complete the worksheet on Idaho Form 51, Estimated Payment of Idaho Individual Income Tax. The worksheet will help you figure out if you owe more tax beyond any payments you’ve made or any amounts withheld from your paychecks or unemployment checks. You can find Form 51 at

To make a payment and avoid a penalty, do one of the following:

  • Mail Form 51 with your check or money order. 
  • Make an online payment through the Idaho State Tax Commission website. See the E-Pay page at The free Quick Pay service lets you make an online payment without creating a Taxpayer Access Point (TAP) account. 
  • Make a payment at any Tax Commission office. When visiting an office, please follow social distancing guidelines by wearing a mask and staying at least 6 feet away from others.

If you qualify for an extension to file, your Idaho tax return and any extra tax payment must be postmarked or sent electronically by October 15.

For more information, call the Tax Commission at (208) 334-7660 in the Boise area or toll free at (800) 972-7660.



Posted 05-13-2021
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This information is for general guidance only. Tax laws are complex and change regularly. We can't cover every circumstance in our guides. This guidance may not apply to your situation. Please contact us with any questions. We work to provide current and accurate information. But some information could have technical inaccuracies or typographical errors. If there's a conflict between current tax law and this information, current tax law will govern.