Per the IRS
There are several ways to find your prior-year AGI:
Preferred Method
You should always retain a copy of your tax return.
On your 2017 tax return, your AGI is on line 37 of the Form 1040; line 21 on the Form 1040-A or line 4 on the Form 1040-EZ.
If you used a paid preparer last year, you might obtain a copy of last year’s tax return from that preparer.
If you are using the same tax preparation software that you used last year, that software will likely have your prior-year tax return for you to access.
If you’re not using the same tax preparation software as last year, you may be able to access your prior-year software and view an electronic copy of your prior-year return.
If you have been issued an Identity Protection (IP) PIN (via a CP01A), you should enter it when prompted by your software. It will serve to verify your identity.
If you are a first-time filer over the age of 16 enter zero as your AGI.
Alternative Methods
If you do not have a copy of your tax return, you may use a Get Transcript self-help tool to get a Tax Return Transcript showing your AGI.
Use Get Transcript Online to immediately view your AGI. You must pass the Secure Access identity verification process. Select the Tax Return Transcript and use only the “Adjusted Gross Income” line entry.
Use Get Transcript by Mail or call 800-908-9946 if you cannot pass Secure Access and need to request a Tax Return Transcript. Please allow 5 to 10 days for delivery. Use only the “Adjusted Gross Income” line entry.
