If you didn’t file taxes last year, your AGI for e-filing purposes is $0. The IRS uses your prior-year adjusted gross income as an identity check when you e-file, and when no return exists in its system, entering zero satisfies that check. Your actual AGI for that missed year is a separate question, and it only matters if you need to go back and file the return or hand the number to a lender, a school, or a government agency.
Why Zero Is the Right Entry
Every electronically filed Form 1040 asks for a prior-year AGI or a Self-Select PIN to verify who you are. If you skipped last year’s return, the IRS has no AGI on file for you, so you enter $0 when the software prompts you. The IRS gives the same instruction to first-time filers over age 16 and to anyone whose prior-year return hasn’t finished processing.1Internal Revenue Service. Validating Your Electronically Filed Tax Return
The zero is a verification workaround. It doesn’t claim you had no income, and it never shows up on your current return. It just tells the system there’s no processed prior-year return to match against. If you actually did file last year and the IRS still rejected your entered AGI, that’s a different problem, and it usually means the IRS adjusted your original figures, processed an amendment, or hasn’t finished processing a paper return you mailed.
Using an IP PIN Instead
An Identity Protection PIN skips the AGI check entirely. If you have one, either because the IRS assigned it after an identity theft case or because you requested it yourself, your e-filing software will ask for that six-digit number in place of your prior-year AGI.1Internal Revenue Service. Validating Your Electronically Filed Tax Return You can request an IP PIN through your IRS online account at any time.2Internal Revenue Service. Get an Identity Protection PIN This route is worth considering if you’ve missed several years and aren’t sure whether a stale return is still floating around in IRS records.
If $0 Still Gets Rejected
Sometimes the IRS rejects an e-filed return even with $0 entered. The usual causes are an old return you’d forgotten about, or someone else having filed under your Social Security number. If that happens, the cleanest fix is to print the return and mail it. The AGI verification requirement only applies to electronic filing, so a paper return goes through regardless. A paid preparer can also e-file for you using an authentication method that doesn’t depend on your prior-year AGI.
Figuring Out Your Actual AGI for the Missed Year
The zero handles e-filing. If you need the real number, whether to file a delinquent return or to give an accurate figure to someone else, you have to reconstruct it.
AGI is total gross income minus a specific set of deductions the IRS calls “adjustments to income.” Gross income covers wages, self-employment earnings, investment income, rental income, retirement distributions, and most other money that came in. Your AGI ends up on line 11 of Form 1040.3Internal Revenue Service. Adjusted Gross Income
The adjustments live on Schedule 1.4Internal Revenue Service. Schedule 1 (Form 1040) – Additional Income and Adjustments to Income Common ones include educator expenses, HSA contributions, the deductible half of self-employment tax, student loan interest up to $2,500 per year, and traditional IRA contributions when you’re eligible. If none of those apply to you, your AGI equals your gross income. For a lot of W-2 employees with no side income and no special deductions, that’s simply box 1 of the W-2.
Use the tax forms and instructions for the specific year you missed. Deduction limits and thresholds shift every year, and prior-year forms are posted on the IRS website.
Pulling Your Income Records
To rebuild your gross income you’ll want the same documents you’d use for a normal return: W-2s, 1099s for freelance income, interest, dividends, and retirement distributions, and any K-1s from partnerships or S corporations. If you no longer have them, the IRS can fill in most of the gaps.
A Wage and Income Transcript lists everything employers, banks, and other payers reported to the IRS under your Social Security number. Transcripts are available for the current year and nine prior years through your IRS online account or by mailing Form 4506-T. The online version caps at roughly 85 income documents per year; beyond that, you’ll have to request the transcript by mail.5Internal Revenue Service. Transcript Types for Individuals and Ways to Order Them
If an employer folded or never issued your W-2, call the IRS at 800-829-1040. The IRS will contact the employer and send you Form 4852, an official substitute for a W-2, which you complete using your best estimates.6Internal Revenue Service. Form 4852 – Substitute for Form W-2, Wage and Tax Statement, or Form 1099-R A final pay stub from that year is the best reference. If the actual W-2 shows up later with different numbers, you’ll amend the return using Form 1040-X.
When a Lender, School, or Marketplace Asks
Lenders, the FAFSA, and health insurance marketplaces often want a prior-year AGI to verify income. If you didn’t file, most of these applications have a non-filer path: you enter zero, check a non-filer box, or estimate current-year income instead. FAFSA has its own workflow for applicants who weren’t required to file. Health insurance marketplaces that base subsidy eligibility on AGI generally let non-filers estimate current income.
Some of these applications try to pull your AGI directly from the IRS through the Data Retrieval Tool. If nothing was filed, that tool comes back empty and you enter the information manually. A Verification of Non-Filing Letter, requested through your IRS online account or by mailing Form 4506-T, is the official proof that no return exists for a given year.7Internal Revenue Service. Get Your Tax Records and Transcripts Financial aid offices and lenders commonly accept it in place of a tax transcript.
Were You Actually Required to File?
Behind the AGI question, there’s usually a bigger one: did you owe a return for that year at all? Whether you had a legal obligation to file for 2025 depends on your gross income, filing status, and age. The IRS publishes dollar thresholds each year, and you only owed a return if your gross income hit or exceeded the number for your situation.8Internal Revenue Service. Check if You Need to File a Tax Return
For 2025 (the return due in April 2026), the filing thresholds for taxpayers under 65 were:
- Single: $15,750 or more in gross income
- Married filing jointly, both under 65: $31,500 or more
- Head of household: $23,625 or more
- Married filing separately: $5 or more
- Qualifying surviving spouse: $31,500 or more
Taxpayers 65 or older had higher thresholds thanks to the additional standard deduction for seniors. A single filer 65 or older didn’t need to file until gross income reached $17,550; joint filers where both spouses were 65 or older had a threshold of $34,700.8Internal Revenue Service. Check if You Need to File a Tax Return
Self-employment has its own, much lower trigger. Net earnings from self-employment of $400 or more required a return no matter what the standard thresholds said.9Internal Revenue Service. Self-Employed Individuals Tax Center That catches a lot of gig workers and side-hustlers who assumed their earnings were too small to bother with.
Filing Anyway Can Pay Off
Even if you fell below the threshold, not filing may have cost you money. Federal income tax withheld from your paychecks only comes back as a refund if you file a return.10Internal Revenue Service. How to Claim the Earned Income Tax Credit Refundable credits like the Earned Income Tax Credit can pay out even when you owe zero tax, but only if a return is filed.11Internal Revenue Service. Earned Income Tax Credit For someone earning $20,000 with two children, the EITC alone can be worth several thousand dollars.
There is a hard deadline attached to any refund. The IRS won’t issue one unless you claim it within three years of the return’s original due date, or two years from when the tax was paid, whichever is later.12Internal Revenue Service. Time You Can Claim a Credit or Refund For a non-filer whose only tax payment was paycheck withholding, the payment is treated as made on the April due date, so the window effectively runs from there. After it closes, the refund is gone, with no appeal.
If You Do Go Back and File
The IRS’s Modernized e-File system accepts the current tax year plus the two immediately preceding years. In 2026 that means you can e-file 2025, 2024, and 2023 returns.13Internal Revenue Service. Benefits of Modernized e-File Anything older has to be printed and mailed to the IRS service center for your area, with the tax year clearly marked on the top of the Form 1040 and on the envelope. Until a delinquent return finishes processing, its AGI won’t appear on IRS transcripts, and the $0 entry keeps working for any current-year e-file.