The $400 Rule: When Your Bill Blows Past the Estimate, Federal Law Gives You a Referee

If you were uninsured or paying cash, the No Surprises Act (45 C.F.R. § 149.610) entitled you to a written Good Faith Estimate before scheduled care. If the final bill from a provider comes in at least $400 over that provider's estimate, you can file a Patient-Provider Dispute Resolution request with CMS (45 C.F.R. § 149.620) within 120 calendar days of the bill date for a small filing fee, and while it is pending the provider cannot send the bill to collections. If the reviewer agrees, you generally pay the estimated amount rather than the billed one.

You asked what it would cost. They gave you a number. You planned around that number. Then the bill arrived — and it's nowhere near what they told you.

Most people assume the estimate was just a guess, shrug, and pay. Here's what the billing office is counting on you not knowing: if you were uninsured or paying cash, that estimate wasn't a guess. It was a federal document. And when the bill blows past it, you can drag the provider in front of a referee.

Exhibit A: The Good Faith Estimate Is Your Right, Not a Courtesy

The No Surprises Act (Public Health Service Act § 2799B-6, implemented at 45 C.F.R. § 149.610) requires providers and facilities to give uninsured and self-pay patients a written Good Faith Estimate (GFE) of expected charges for scheduled care — and to give one on request even before you book anything.

The timing is spelled out in the regulation:

Care scheduled 10 or more business days out: the GFE must arrive within 3 business days of scheduling.

Care scheduled 3 to 9 business days out: within 1 business day.

You ask for an estimate without scheduling: within 3 business days of your request.

If nobody offered you one, that's not you missing a memo. That's them skipping a federal requirement. You are entitled to it in writing, every time, before scheduled care.

Exhibit B: The $400 Trigger

Here's where the estimate grows teeth. Under the Patient-Provider Dispute Resolution (PPDR) process (45 C.F.R. § 149.620), if your final bill from a provider or facility is at least $400 more than that provider's Good Faith Estimate, you can ask the federal government to send the dispute to an independent reviewer.

The mechanics, straight from CMS:

You must start the dispute within 120 calendar days of the date on the initial bill.

The filing fee is $25 — and if the reviewer sides with you, that $25 comes off what you owe.

While the dispute is pending, the provider can't send that bill to collections or charge you late fees on it, and if it's already in collections, collection has to pause.

If the reviewer agrees the charge wasn't justified, you generally pay the estimated amount, not the inflated one. If they side with the provider, you pay the billed amount — so this is a tool for real gaps, not a coupon. You file it with CMS in writing, at CMS.gov or through the federal help desk at 1-800-985-3059.

Exhibit C: What This Doesn't Cover — Yet

Two honest caveats, because you deserve the whole map, not the highlight reel.

First, the $400 threshold applies per provider or facility, not to the total across your whole episode of care. A bill that's $300 over from the surgeon and $300 over from the lab may not qualify, even though you're $600 in the hole.

Second, the GFE right currently protects uninsured and self-pay patients. If you have insurance, the No Surprises Act still shields you from many surprise out-of-network bills — emergency care, out-of-network providers at in-network facilities, air ambulances — but the insured version of the advance estimate (the "Advanced EOB") is still stuck in federal rulemaking as of this year. Insured and fighting a bill? Your weapons are the itemized bill, coding errors, and the appeal process instead.

Your Move

Before scheduled care: the Good Faith Estimate is yours, in writing. Keep it. It's your baseline exhibit.

When the bill arrives: put the bill and the GFE side by side, provider by provider. Same provider, $400+ over? You have 120 days. Calendar it. Upload the bill and BillFighter reads every line and points out the charges worth questioning; its Dispute Letter puts them on the record with the provider, by certified mail with the delivery record.

File the federal dispute: CMS, $25, in writing, inside the 120 days. It runs alongside your letter to the provider. Paper creates a record. Records win fights.

The system priced in your silence. The No Surprises Act un-priced it — but only for the people who know the rule exists. Now you do.

Check my bill, free → — BillFighter reads every line, points out the charges worth questioning, and shows which letter fits. No account needed to start.

BillFighter is a tool that helps you understand and fight your bills. It is not a law firm and this isn't legal advice — for legal advice about your specific situation, talk to a lawyer.