How to File an Amended Idaho Return

Instructions, Resources on how to prepare and e-File Idaho Tax Returns or how to prepare an Extension and/or previous Year Tax Returns

Prepare, eFile a ID + IRS Tax Return: Detailed eFile.com Service Overview

Prepare only a ID State Return without an IRS return. Details

Step by Step instructions on how to only Prepare and Download - not eFile - State Returns on eFile.com.

File an Idaho Tax Amendment

You can prepare an Idaho Tax Amendment for the 2023 tax year here on eFile.com; the amendment can not be e-filed. After you have prepared the amendment, download the PDF from your My Account, check the box and mail in the form to the address listed below. For other tax years complete the form below before you print, sign and mail in the form.
Option 1: Sign into your eFile.com account, modify your Return and download/print the ID Form 40 (residents) or Form 43 (nonresidents and part-year residents) under My Account. Check the "Amended Return" box, sign the form, and mail it to one of the addresses listed below.
Option 2: If you don't have an eFile.com account follow the step by step instruction on how to prepare a tax return/amendment.
Option 3: If you want to do the math on your own paper return then complete, sign ID Form 40 or Form 43 - Print, Mail the Form to ID State Tax Commission to:
Idaho State Tax Commission
P.O. Box 56
Boise, ID 83756-0056

ID Tax Amendment Form 40 or 43
This Form can be used to file a: Tax Return, Tax Amendment, Change of Address. Check the "Amended Return" box on the Form.

Step 1: Download, Complete Form 40 (residents) or 43 (nonresidents and part-year residents) for the appropriate Tax Year below.
Step 2: Sign, Mail Form 40 or 43 to one of the addresses listed above

Check this box on the ID Tax Return Form 40 or 43. This Form can be used to file a: Tax Return, Tax Amendment, Change of Address.

Current Tax Year only: Prepare online on eFile.com until the October Deadline. When done Print, Sign and Mail in - Your Tax Amendment, Address Change, etc.

After Oct. Deadline Prepare, Print, Sign and Mail-In - see address above, ID Form 40 or Form 43

How to correct a rejected Tax Return

If your ID Tax Return was rejected by the ID Tax Agency - not eFile.com - instructions on how to correct a rejected Idaho Tax Return.

For all Tax Years prior to current tax year Prepare, Print, Sign and Mail-In - see addresses above - your Tax Amendment as soon as possible. Select the appropriate form (Form 40 or 43) for the Tax Year you are amending. You will also file an IRS Tax Amendment Form 1040X.

Check Your ID Tax Amendment Status

1. Call the ID State Tax Commission at (800) 972-7660
2. Contact the ID State Tax Commission

Idaho Refund Deadlines

A. Three years from the due date of the original tax year return, including valid filing extensions.
B. One year from the final determination of the amended federal return or federal change, whichever is later, provided that the allowable refund is not more than the decrease in Idaho tax attributable to the federal change or correction.
C. Two years from the payment of an assessment, provided the amended return raises issues relating only to the prior assessment and the refund does not exceed the amount of tax paid on the prior assessment.
D. Two years from the filing of an amended Idah return resulting in the payment of additional tax, provided that the current amended return raises issues relating solely to the prior amended return and that the refund does not exceed the amount of the tax payment made as a result of the prior amended return.
Additional Idaho Tax Income Taxes Deadlines

Idaho Income Tax Penalties

Find out how Idaho Late Filing and Late Payment Penalties are calculated.
For IRS Tax and Late Filing Penalties we have an easy to use tool: The PENALTYucator.

File an IRS Tax Amendment by Tax Year

Instructions on how to prepare an IRS Tax Amendment on eFile.com, however the IRS does not accept Tax Amendments electronically.