1099-INT box guide
1099-INT Box 4: Federal income tax withheld
Reconcile backup withholding from interest with the federal withholding claimed on Form 1040.
Return destination
Where the amount goes
Form 1040 federal income tax withholding
1099-INT
Return to the complete form guide and reconciliation worksheet.
Checks before filing
- Match withholding to payer statements.
- Claim the withholding separately from the interest income.
- Ask the payer about a correction when the amount or taxpayer ID is wrong.
How Box 4 works
Box 4 reports backup withholding taken from your interest payments, not routine voluntary withholding — interest isn't wages, so there's no W-4-style election involved. Backup withholding on interest generally applies when a payer wasn't furnished a correct taxpayer identification number, and the instructions apply it against the amounts reportable in Box 1, Box 3, and Box 8, so withholding can appear even against interest that is otherwise tax-exempt.
U.S. recipients avoid backup withholding by keeping a current Form W-9 on file with each bank or broker, so the first troubleshooting step when Box 4 shows an unexpected amount is confirming the name and taxpayer ID on file with that specific payer match IRS records exactly — a mismatch at one institution only triggers withholding on that account, not across every account you hold. Multiple Forms 1099-INT from different payers can each carry their own separate Box 4 figure; total the withholding across all of them before entering the combined amount on Form 1040, the same way Box 1 interest is combined across payers.
Never net Box 4 against Box 1, Box 3, or Box 8 when totaling income — the full interest amount is still reported as income, and the withholding is claimed separately as a payment already made toward the year's tax liability. If the taxpayer ID or name on the form doesn't match your records, ask the payer for a corrected Form 1099-INT rather than adjusting the withholding figure yourself; a corrected form is also the right channel if withholding was applied in error.
Worked example
A taxpayer's Form 1099-INT shows Box 1 of $500 in interest income and Box 4 of $120 in backup withholding after a W-9 mismatch flagged the account earlier in the year. The taxpayer still reports the full $500 as interest income, then separately claims the $120 as federal income tax already paid, which reduces the balance due or increases the refund.
Related 1099-INT boxes
Box 1: Interest income
Understand taxable bank and investment interest and where it enters the federal return.
Box 2: Early withdrawal penalty
Trace an early withdrawal penalty from Form 1099-INT to the eligible Schedule 1 adjustment.
Box 3: U.S. savings bond and Treasury interest
Separate federally taxable Treasury interest that may receive different state income-tax treatment.
Box 8: Tax-exempt interest
Report federally tax-exempt interest without including it in ordinary federal taxable interest.
Frequently asked questions
What does Box 4 mean on 1099-INT?
Box 4 is federal income tax withheld by the payer, often under backup-withholding rules. It is a payment toward tax, not a reduction of interest income.
Why is my bank withholding tax from my interest payments without me asking?
This is backup withholding, generally triggered when the payer doesn't have a correct taxpayer identification number on file for you — a missing or mismatched Form W-9 — rather than a voluntary election like paycheck withholding.
Do I subtract Box 4 from my interest income before reporting it?
No. Report the full interest amount from Box 1 (and Box 3 or Box 8 if applicable) as income, and claim Box 4 separately as federal income tax withheld — a payment toward your tax liability, not a reduction of the interest itself.
How do I stop backup withholding on future interest payments?
Provide the payer a correct, current Form W-9 so your taxpayer identification number is properly on file; the payer should stop applying backup withholding on that account once the certification is in good order.