I received a W-2c form for 2024 after I had already filed my 2024 taxes last year. On which year tax forms do I need to add my W-2c form?

[librarylady08]

Is it possible to add it to the 2025 tax return? or would I have to amend my 2024 taxes?

[xmasbaby0]

What was the change to the W-2?   The change might not be relevant enough to require you to amend.

[SharonD007]

No, you  can't add a W-2C form for 2024 to your 2025 tax return. You may need to amend your 2024 taxes if your income, taxes, or deductions have changed on the W2-C. Compare the information in boxes 1-20 on your W-2C with your original W-2. If the amounts differ, you can file an amendment for 2024. If the new information doesn't change your original refund or balance due, there's no need to file an amendment.

Please review the TurboTax Help articles Refer to the TurboTax Help articles How do I add a W-2, W-2c or form after I've already filed?  and How do I amend my federal tax return for a prior year? for specific instructions.

[Mike9241]

Not all changes require filing an amended return. If you post the box numbers that changed, we could advise further

[librarylady08]

Thank you for your help. It looks like there was in increase on 12a, previously reported was $4,768.07 and corrected amount is $4,876.91... a $108.84 difference. 

[VolvoGirl]

What code is in box 12a?   What is the amount for?

[librarylady08]

Oh right, sorry about that, it is code "D" for Elective deferrals to a section 401(k) cash or deferred arrangement. Also includes deferrals under a SIMPLE retirement account that is part of a section 401(k) arrangement. 

[AmyC]

If the only difference is box 12, 401K contributions, your taxable income will not change and an amended return is not needed. 

File an amended return states:

File an amended return if there's a change in your:

• Filing status
• Income
• Deductions
• Credits
• Dependents
• Tax liability