Idaho State Tax Commission

Idaho State Tax Commission

Tax Commission News Release

Need an extension to file your Idaho income taxes?

BOISE, IDAHO — April 12, 2018 — If you can’t file your 2017 Idaho income tax return by the April 17 due date, you may be able to get an automatic, six-month extension if you pay enough of your total tax.

To qualify, you need to pay:

  • An estimated 80 percent of the tax you owe for 2017, or 
  • 100 percent of the total tax reported on your 2016 income tax return

You must make your payment by April 17.

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. You’ll be charged 4 percent interest annually 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 the payments you may have made or the amounts that may have been withheld from your paychecks or unemployment checks. You can find Form 51 at and in the 2017 Idaho income tax packet.

To make a payment and avoid a penalty:

  • 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 an account. 
  • Make a payment at any Tax Commission office.

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

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




Posted 04-12-2018
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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.