How to use the tax refund claim deadline calculator
Korea gives taxpayers a flat five years from the statutory filing deadline to ask for a correction. The federal rule in the United States is different and has two moving parts: a refund claim is timely if it is filed within 3 years from the time the return was filed or 2 years from the time the tax was paid, whichever expires later. Enter your dates and the calculator shows both and tells you which one controls.
How the dates are counted — periods stated in years run to the same calendar date, so a return filed on April 15 gives a 3-year date of April 15 three years later. If that date has no counterpart in the final month, the calculator uses the last day of that month, and the same rule is applied to both the 3-year and the 2-year line. A deadline landing on a Saturday, Sunday or legal holiday moves to the next business day under 26 U.S.C. 7503.
Legal basis — the two-part period comes from 26 U.S.C. 6511(a), and a claim is normally made on an amended return such as Form 1040-X. A return filed before its due date is treated as filed on the due date under 26 U.S.C. 6513(a), which is why the optional due date field matters. Separate lookback limits in 26 U.S.C. 6511(b)(2) can cap how much is actually refundable. Figures are current as of September 2026.
This calculator is for reference only and is not legal advice. Consult a licensed attorney or CPA about your specific situation.
Frequently asked questions
When no return was filed, 26 U.S.C. 6511(a) leaves only the 2-year period measured from the time the tax was paid, so the payment date becomes the controlling one.
No. Even a timely claim is limited by the lookback rules in 26 U.S.C. 6511(b)(2), which restrict the refund to tax paid within a set period before the claim. The amount depends on the facts, so ask a tax professional.