If both parents claim a child on taxes, the IRS catches the duplicate Social Security number, rejects the second e-filed return on the spot, and if both parents hold their ground, opens an audit that ends with one parent repaying the refund plus 7% annual interest, penalties, and possibly a multi-year ban from claiming child-related credits. The IRS doesn’t follow your divorce decree. It applies its own tie-breaker rules, and the first question is which parent the child spent more nights with during the year.
What the IRS Does First
Whoever files first wins the opening round. The IRS computers won’t accept two electronic returns listing the same dependent SSN, so the second parent’s e-file is rejected immediately. That parent then has to choose: drop the child and refile, or mail a paper return still claiming the child. Paper-filing pushes both returns into the system and triggers a review.
Once two returns claiming the same child are in the system, the IRS mails each parent a Notice CP87A. This is not an audit. It tells you someone else claimed the same child and asks you to review your claim. If you realize the child isn’t your dependent, you file an amended return on Form 1040-X. If you believe you’re right, you do nothing.
If neither parent backs down, the IRS escalates to an audit, usually with a CP75 notice. You get 30 days to document that the child lived with you. Miss that window and the IRS disallows your claim and issues a notice of deficiency for the tax, penalties, and interest.
How the IRS Decides Who Gets the Claim
The tie-breaker is residency. The parent the child lived with for more nights during the tax year is the “custodial parent” for federal tax purposes, and that parent holds the default right to claim the child. State custody labels don’t matter. Child support payments don’t matter. Nights do.
If the nights split exactly evenly, the claim goes to the parent with the higher adjusted gross income. That’s a pure math question, not a fairness question.
And the divorce decree, however clearly it assigns the dependency, does not bind the IRS. If the custodial parent files first and claims the child, the IRS will side with that parent regardless of what a state judge ordered. The noncustodial parent’s recourse is back in state court, not with the IRS.
What Counts as Proof During the Audit
Your own statement isn’t enough. The IRS wants third-party records tying the child’s address to your home during the tax year. Useful documents include school enrollment records, medical records, a lease or mortgage statement, childcare provider records, and government benefits paperwork listing the child’s address. A noncustodial parent claiming the child must also attach a signed Form 8332 and, if relevant, the divorce decree or custody agreement.
What the Wrong Claimant Owes
The parent whose claim the IRS disallows has to pay back the refund they received or the tax they underpaid, with interest running from the original filing deadline. The IRS charges 7% annual interest on underpayments, compounded daily. On a $3,000 underpayment that sits for a year, that’s roughly $210 in interest alone.
On top of interest, the IRS can assess an accuracy-related penalty of 20% of the underpayment. If the agency concludes the claim was fraudulent rather than simply wrong, the penalty rises to 75% of the underpayment attributable to the fraud under federal law.
The Two- and Ten-Year Credit Bans
This is the consequence most parents don’t see coming. If the IRS decides your claim was reckless or intentionally wrong, it can bar you from claiming the Earned Income Tax Credit, Child Tax Credit, and related credits for two full years. If the claim is deemed fraudulent, the ban runs ten years. During the ban, you cannot claim those credits even if you later have a child who clearly qualifies.
After a ban ends, or any time you’ve had one of these credits disallowed in a prior year, you must file Form 8862 with your next return claiming any of the affected credits. The IRS will not release the credit without it.
Why the Credits Matter So Much Here
Losing the dependent claim for 2026 wipes out the full Child Tax Credit of up to $2,200 per qualifying child, including the refundable portion of up to $1,700 paid through the Additional Child Tax Credit.
It can also wipe out the EITC, which for 2026 reaches $4,427 with one qualifying child, $7,316 with two, and $8,231 with three or more, compared to just $664 for a worker with no qualifying children. The EITC is where lower-income parents feel the loss most sharply, and it is important to understand that the EITC cannot be transferred. Only the custodial parent can claim it, no matter what the parents agree to.
Filing status is a third hit. A parent who loses the qualifying child may also lose Head of Household status and drop to Single, which for 2026 means a $16,100 standard deduction instead of $24,150.
Form 8332 Is the Only Way to Transfer the Claim
If the parents want the noncustodial parent to claim the child, the custodial parent has to sign Form 8332 releasing the dependency for a specific year or range of years. The noncustodial parent attaches a copy to their return every year they claim the child. A divorce decree alone will not do this work. If the custodial parent refuses to sign, the noncustodial parent cannot legally claim the child on a federal return.
A few limits worth knowing:
- Form 8332 only transfers the Child Tax Credit, Additional Child Tax Credit, and Credit for Other Dependents. It does not transfer the EITC or Head of Household filing status, which stay with the custodial parent.
- The release can be revoked. A custodial parent who previously signed can complete Part III of Form 8332 to revoke the release for future years, with a copy provided to the noncustodial parent. The revocation cannot undo a year already released.
Fixing an Incorrect Claim
If you realize you’re the one who shouldn’t have claimed the child, file Form 1040-X to remove the dependent, adjust your filing status if it changes, and recalculate the tax. You can file 1040-X electronically for the current year and the two prior years. Pay the balance as fast as you can because interest keeps running from the original due date, not from the date you amend. The IRS offers installment agreements if you can’t pay in full, but interest continues to accrue until the balance is cleared.
Preventing a Repeat Next Year
The cleanest prevention is a written agreement between parents about who claims the child each year, paired with a signed Form 8332 for any year the noncustodial parent takes the claim. Get the form signed well before filing season and keep the original.
If you’re worried the other parent will claim the child without permission, request an Identity Protection PIN for your child from the IRS. An IP PIN is a six-digit number assigned annually that must appear on any return listing that SSN. A return without the correct PIN gets rejected.
Parents can request an IP PIN for a dependent under 18 by filing Form 15227 if adjusted gross income is below $84,000 for individual filers or $168,000 for joint filers. If you’re over those thresholds or can’t verify your identity online, you can authenticate in person at an IRS Taxpayer Assistance Center with a government-issued photo ID for yourself and two forms of ID for the child, such as a birth certificate and Social Security card. The PIN typically arrives by mail within three to six weeks, and a new one is issued automatically each year.