If your tax refund came in smaller than you expected, the reason is almost always one of two things: the IRS corrected something on your return, or another agency intercepted part of the money to cover a debt you owe. Under 26 U.S.C. § 6402, the IRS can apply your overpayment to your own past-due federal tax first, and it must hand off portions of what’s left to federal and state agencies that have certified debts against you.1Office of the Law Revision Counsel. 26 USC 6402 – Authority to Make Credits or Refunds The notice you receive tells you which happened, and that determines what you can do next.
How to Tell Which Happened
Before you call anyone, find the notice. The IRS and the Bureau of the Fiscal Service send different letters depending on what changed, and each one contains reference numbers a representative will ask for.
- CP12: The IRS corrected a math error and your refund changed, but you’re still getting money back.2Taxpayer Advocate Service. Notice CP12
- CP11: The IRS corrected an error and you now owe a balance, with a payment due date on the notice.3Internal Revenue Service. Understanding Your CP11 Notice
- CP13: The IRS corrected an error and your account is now at zero. You don’t owe, but your refund is gone.4Internal Revenue Service. Understanding Your CP13 Notice
- CP49: Your refund was applied to a past-due tax balance from another year.5Internal Revenue Service. Understanding Your CP49 Notice
If the reduction came from a non-tax debt, the notice comes from the Bureau of the Fiscal Service rather than the IRS and names the creditor agency that received the money. If no notice has arrived and you want to know whether a non-tax offset hit your refund, call the Treasury Offset Program automated line at 800-304-3107. Hearing-impaired callers can reach a relay operator at 800-877-8339.6Bureau of the Fiscal Service. Frequently Asked Questions for Debtors in the Treasury Offset Program
IRS Corrections That Shrink a Refund
The most common reason for a smaller refund is a correction the IRS made during processing. Automated systems check every calculation, and a simple arithmetic slip or a number carried incorrectly between lines triggers a recalculation. The tax code calls these “math errors,” and the category is broader than it sounds.
Mismatched Social Security numbers fall in the same bucket. If an SSN for you, your spouse, or a dependent doesn’t match Social Security Administration records, the IRS may deny credits tied to that person and lower your refund.7Internal Revenue Service. 21.5.4 General Math Error Procedures This shows up most with the Child Tax Credit, the Earned Income Tax Credit, and education credits, all of which require valid SSNs.
Income mismatches are the bigger issue. Employers and financial institutions send copies of your W-2s and 1099s directly to the IRS.8Internal Revenue Service. About Form W-2, Wage and Tax Statement The Automated Underreporter program compares what you reported to those third-party records. If you left off freelance income from a 1099-NEC, forgot bank interest on a 1099-INT, or understated wages, the system flags the gap, recalculates your tax, and shrinks the refund.
Credit denials cause the largest drops. The Child Tax Credit, worth up to $2,200 per qualifying child, requires that the child be under 17, have a valid SSN, and live with you for more than half the year.9Internal Revenue Service. Child Tax Credit If IRS records show the child was claimed on another return or the age doesn’t match, the credit is denied. The EITC requires earned income, investment income below a set threshold, and U.S. citizenship or resident-alien status for the entire year.10Internal Revenue Service. Who Qualifies for the Earned Income Tax Credit (EITC) For 2025 returns filed in 2026, the maximum EITC ranges from $649 with no qualifying children to $8,046 with three or more, so losing it can wipe out thousands of dollars. Filing-status mistakes, like claiming head of household when you should have filed single, push you into lower phase-out thresholds for multiple credits at once.
When the IRS Keeps Your Refund for Past Taxes
If you owe back taxes from a prior year, the IRS doesn’t send your refund to a separate agency. It keeps the money. Under 26 U.S.C. § 6402(a), the agency credits any overpayment against your existing federal tax liability before releasing whatever remains.1Office of the Law Revision Counsel. 26 USC 6402 – Authority to Make Credits or Refunds
The refund pays down the debt in a fixed order: unpaid tax first, then penalties, then accrued interest.11Internal Revenue Service. Topic No. 653, IRS Notices and Bills, Penalties and Interest Charges If your refund is larger than the debt, you get the difference. If the debt is larger, your refund disappears and the remaining balance keeps accruing interest. The CP49 notice explains that all or part of your refund was applied to a tax debt.5Internal Revenue Service. Understanding Your CP49 Notice
When Another Agency Takes Your Refund
Even after the IRS is done, your refund may not reach your bank account. The Bureau of the Fiscal Service runs the Treasury Offset Program, which intercepts federal payments headed to people who owe delinquent debts to federal or state agencies.12Bureau of the Fiscal Service. Treasury Offset Program The program matches your name and SSN against a database of certified debts and diverts the funds before deposit.
The statute sets a priority order when multiple agencies are competing for the same refund:1Office of the Law Revision Counsel. 26 USC 6402 – Authority to Make Credits or Refunds
- Past-due child support comes first. If a state child support agency has certified that you’re behind, that offset happens before any other non-tax debt.
- Federal non-tax debts, such as overpayments of Social Security benefits or delinquent SBA loans, come next.
- State income tax debts certified by a state government come after federal non-tax debts.
- State unemployment compensation overpayments come last.
One current exception: the Department of Education announced in January 2026 that it would delay involuntary collections on federal student loans, including Treasury Offset Program seizures, while it implements changes to the student loan system. If you’re in default on federal student loans, your refund may not be offset for now, though the policy could change.
Tax refunds are fully eligible for offset, with no minimum amount protected. Some other federal payments are exempt or partially exempt from offset depending on the type of debt, but refunds don’t get that shield.13eCFR. Subpart A – Disbursing Official Offset Once a creditor agency certifies the debt, the IRS has no discretion to stop or reverse the offset. After the seizure, the Bureau of the Fiscal Service sends a notice showing the date and amount, the creditor agency that received the money, and a contact point at that agency.14Bureau of the Fiscal Service. Treasury Offset Program – How TOP Works
Getting Your Share Back on a Joint Return
If you filed jointly and your spouse is the one with the debt, the offset can swallow your portion of the refund too. The IRS treats a joint refund as a single pool and doesn’t automatically separate each spouse’s contribution.
Form 8379, the Injured Spouse Allocation, is how you get your share back. You qualify if you filed jointly, part of the refund was seized because of your spouse’s past-due obligation, and the debt belongs solely to your spouse. Qualifying debts include past-due child support, federal tax debt, state income tax, state unemployment overpayments, and federal non-tax debts like student loans.15IRS. Instructions for Form 8379 – Injured Spouse Allocation
You can attach Form 8379 to your joint return or file it separately after learning about the offset. The form must be filed within three years of the original return’s due date (including extensions) or within two years of the date you paid the tax that was offset, whichever is later.16Internal Revenue Service. Instructions for Form 8379 Processing runs about 11 weeks if you e-file it with your return, 14 weeks on paper, and roughly 8 weeks if you submit it after the return has already been processed.17Internal Revenue Service. Injured Spouse Don’t confuse this with innocent spouse relief on Form 8857, which deals with a spouse who underreported income or claimed false deductions on the joint return.
How to Push Back on an Adjustment
You are not required to accept every change. How you dispute one depends on what kind of adjustment it was.
Math Error Assessments
When the IRS corrects a math error, the notice starts a 60-day clock. Within that window you can request an abatement, and the IRS must reverse the change on request. During those 60 days, the agency cannot levy your assets or begin collection on that assessment.18Office of the Law Revision Counsel. 26 USC 6213 – Restrictions Applicable to Deficiencies; Petition to Tax Court If you respond by mail, the postmark date controls whether you met the deadline.7Internal Revenue Service. 21.5.4 General Math Error Procedures Reversing the assessment doesn’t decide the underlying question. It forces the IRS to use full deficiency procedures instead of the abbreviated math-error process, which gives you more formal protections.
Deficiency Notices
For larger disputes where the IRS proposes additional tax beyond a math correction, you will receive a Notice of Deficiency, sometimes called a “90-day letter.” You have 90 days from the mailing date to file a petition with the United States Tax Court, or 150 days if you are outside the country. Filing the petition prevents the IRS from assessing the disputed amount until the court rules.
Proving a Child Lived With You
If the IRS challenges a child-related credit, you may need to show the child actually lived with you. The agency accepts school records, medical records, daycare documentation, and letters on official letterhead from schools, medical providers, or social service agencies showing your name, the child’s name, a shared address, and the dates.19IRS. Form 886-H-DEP – Supporting Documents for Dependents Letters from relatives don’t count.
Non-Tax Offsets
Disputing a Treasury Offset Program seizure means going to the creditor agency, not the IRS. Before referring a debt for offset, an agency must send you a letter explaining what you owe and your right to dispute it.6Bureau of the Fiscal Service. Frequently Asked Questions for Debtors in the Treasury Offset Program If that letter never arrived, or if the debt isn’t yours, contact the agency directly using the information on the TOP notice.
Downstream Consequences of a Credit Denial
Losing a credit on this year’s return can follow you. If the IRS determines your claim was due to reckless or intentional disregard of the rules, you are banned from claiming the EITC, CTC, or related credits for two years after the final determination. If the denial was based on fraud, the ban stretches to ten years.20Internal Revenue Service. What to Do if We Deny Your Claim for a Credit
Once a ban ends, or if your denial was for a reason other than recklessness or fraud, you don’t simply resume claiming the credit. You must file Form 8862 to demonstrate that you now meet every eligibility requirement. This applies to the EITC, CTC, Additional Child Tax Credit, Credit for Other Dependents, and the American Opportunity Tax Credit.21Internal Revenue Service. Instructions for Form 8862 – Information to Claim Certain Credits After Disallowance If you want to appeal a ban, you must file Form 8862 with supporting documentation and mail the return. The IRS rejects electronically filed returns that attempt to claim a banned credit.