IRS Form 870

What Form 870 is

Form 870’s full title is Waiver of Restrictions on Assessment and Collection of Deficiency in Tax and Acceptance of Overassessment. It is the IRS’s standard agreement form for audit results. By signing it you give up, for the amount shown, the protections IRC 6213(a) normally gives you before the IRS can assess more tax. IRC 6213(d) lets you waive those restrictions “at any time,” for “the whole or any part of the deficiency.”

The IRS manual (IRM 4.10.8, revised August 28, 2025) says forms in the 870 series are used “in excepted agreed cases and unagreed cases requiring a Preliminary (30-day) letter.” In plain terms, you will usually see a Form 870 in three situations:

• The report has no signature line. When the examiner issues Form 4549-A, the report without a place to sign, “examiners typically prepare and provide Form 870” so you can agree. For individual returns, the manual pairs Form 4549-A with Form 870 in unagreed cases.
• You agree with only part of the audit. The manual says Form 870 “is used as a waiver in partially agreed cases” in both office and field audits.
• Your agreement depends on a condition, such as a review or extra processing step, which the manual calls an “excepted agreed” case.

Form 870 is prepared by the IRS for your case; you don’t download and fill it in yourself. Not sure which documents you have? See the audit letter lookup.

Form 870 vs Form 4549

Both forms are agreements, and both have the same legal effect on the amount you sign for. The difference is packaging.

The Appeals manual calls both “Form 870-type” agreements (IRM 8.6.4.4.2). See Form 4549 explained. The reasons for each change are on Form 886-A or the explanations attached to the report.

What signing Form 870 does, and what it doesn't

What it does:

• Lets the IRS assess without a notice of deficiency for the amount you sign for. You lose the 90-day letter and the Tax Court’s prepayment review for that amount. See notice of deficiency.
• Starts the billing. Expect a balance-due notice such as a CP14 for anything unpaid.
• Can stop interest if the IRS is slow. Under IRC 6601(c), if the IRS does not make notice and demand for payment within 30 days after you file the waiver, interest stops from the 31st day until it does.
• Can serve as a refund claim. If the audit found you overpaid, the manual says the IRS treats a signed Form 870 agreeing to the overassessment as a valid claim for refund.

What it doesn’t do:

• It doesn’t end the matter for good. The manual says signing “does not preclude assertion of a further deficiency” by the IRS, or “a request for further consideration of the issues by the taxpayer.” The IRS manual quotes the form’s own instructions: “It will not prevent us from later determining, if necessary, that you owe additional tax.”
• It doesn’t extend the statute of limitations. IRM 25.6.22.2 says waivers such as Form 4549 and Form 870 “are not consents to extend” the assessment period. That is Form 872.
• It doesn’t stop interest that has already built up. Interest on agreed tax generally runs from the return’s due date at the federal short-term rate plus 3 percentage points, reset quarterly (7% (IRS.gov, Jul-Dec 2026) this quarter).

Partial agreement: signing for some items only

Form 870 is how you settle the parts of an audit you accept while still fighting the rest. The manual describes the package: an “Agreed” Form 4549-A that “reflects only the adjustments for which the taxpayer indicated agreement,” and a Form 870 that “reflects only the agreed deficiency.” Examiners give a response date, “generally 15 days” according to the manual, often with Letter 1967; the date on your letter controls.

Once the IRS has your signed Form 870, it assesses the agreed amount. The disputed items then follow the normal unagreed route: a 30-day letter, a protest to Appeals and, if needed, a notice of deficiency. Paying the agreed part early limits the interest on it.

Form 870-AD: the Appeals version

If your case settles in the IRS Independent Office of Appeals, you may be asked to sign Form 870-AD instead, Offer to Waive Restrictions on Assessment and Collection of Tax Deficiency and to Accept Overassessment. The Appeals manual (IRM 8.6.4.4, revised June 16, 2020) says forms ending in “AD” (for “Appeals Division”) “are used only by Appeals,” when “material mutual concessions are made” or when you ask for greater finality. Where neither applies, Appeals uses a regular Form 870-type agreement, including Form 4549.

Under IRS Policy Statement 8-3, the IRS will not reopen a case closed on Form 870-AD except for fraud, malfeasance, concealment or misrepresentation of a material fact, an important mathematical mistake, or a listed transaction (IRM 8.6.1.7). The manual also warns that a tentative Appeals agreement not yet finalized on Form 870-AD or a closing agreement can be renegotiated if the law changes. For still more finality, Appeals can use a closing agreement (Form 866 or Form 906). How Appeals reaches a settlement is covered in agree or appeal.

Your options when you receive Form 870

How to sign and send it

1. Check every line. Your name, taxpayer ID, tax years and amounts should match the report. A Form 870 for a partial agreement should show only the agreed deficiency.
2. Sign the way you filed. On a joint return, the Appeals manual says agreement forms need both spouses’ signatures (or an authorized representative’s) unless the deficiency is paid in full.
3. Send it as the letter says. The manual says the IRS can accept a signed Form 4549 or Form 870 by fax. Mail and keep proof of the date. A cover letter helps.
4. Keep a full copy of the form, the report and your cover letter.
5. Plan the payment. Publication 3498 says that if the total due is less than $100,000 (IRS.gov, 2026) and you pay within 21 calendar days of the bill, no more interest or penalties are added. If you can’t pay, see options for an audit bill you can’t pay.

Mistakes to avoid

• Signing to make the audit go away. You give up the Tax Court’s prepayment review for that amount. Sign only for changes you accept.
• Signing a full waiver when you agree with only part. Ask for a partial agreement instead.
• Assuming the IRS can’t come back. A regular Form 870 does not stop the IRS from proposing more tax while the statute is open.
• Confusing Form 870 with Form 872. One agrees to tax; the other extends the time to assess it.

Free help is available: Low Income Taxpayer Clinics represent eligible taxpayers in audits for free or a small fee, and the Taxpayer Advocate Service (877-777-4778 (IRS.gov, 2026)) helps when an IRS problem causes hardship. Global Gate Tax Relief offers a free consultation to review what you are being asked to sign; if it takes the case, it quotes a flat fee upfront and promises no outcome. Request a free review or call 1-877-800-8180.

Frequently asked questions

Keep reading in the IRS Audit Guide

• The 30-day letterAgree, agree in part, or request Appeals.
• Notice of deficiency (90-day letter)The Tax Court right you keep by not signing.
• Form 4549, the audit reportThe report with its own signature line.
• Agree or appeal?How to decide whether to sign.
• Form 872, extending the statuteThe other audit form the IRS may ask you to sign.