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The Good Faith Estimate Dispute Process: How the $400 Rule Actually Works

EOBCheck · Updated August 25, 2026 · 7 min read

If you're uninsured or paying out of pocket, you're generally entitled to a written cost estimate before a scheduled medical service. If your final bill comes in significantly higher, federal rules give you a real, formal way to challenge it. Here's how that actually works.

What a Good Faith Estimate actually is

A Good Faith Estimate (GFE) is a written estimate of expected charges for a scheduled service, given to uninsured or self-pay patients before the service happens. It's meant to prevent exactly the situation this article is about — a final bill that bears no resemblance to what you were told to expect.

The $400 rule

If your final bill ends up $400 or more above your Good Faith Estimate, from a single provider or facility, you may be eligible to dispute that charge through a federal process rather than just negotiating informally. CMS's official rights fact sheet confirms this threshold as part of the No Surprises Act.

Important nuance: this threshold is calculated per provider or facility, not combined across your whole treatment. If three different providers each billed you $300 over their own individual estimates, none of them alone crosses $400 — even though your combined overage is $900. This is one of the most commonly misunderstood parts of the rule.

Who this applies to

Eligibility details and filing windows can shift over time, so treat this as a starting point for your own research, not a final legal determination — verify your specific situation before assuming you qualify or don't.

How to actually file a dispute

  1. Gather your Good Faith Estimate and your final, itemized bill.
  2. Confirm the gap is $400 or more from that one provider specifically.
  3. Look up the current federal Patient-Provider Dispute Resolution process — this is administered through HHS and has its own filing window after you receive the bill, so don't sit on this for months.
  4. Submit your estimate, your bill, and a short explanation of the discrepancy.
Before you file: it's worth first asking the provider directly for a written explanation of the gap. Sometimes what looks like a GFE violation is actually an added service you didn't originally expect (which may or may not still qualify), and a quick conversation can save you the formal filing entirely — or make your dispute stronger if you do file.

What this process can and can't do

A successful dispute can result in your bill being reduced to the estimate amount (or close to it), or a mediated settlement. It won't erase a bill that was accurate and simply higher than you personally expected without a GFE ever being issued — the whole process is anchored to that written estimate existing in the first place.

Just want a quick $400-rule check?

Use the free standalone calculator — enter your estimate and final bill, get an instant answer, no EOB needed.

Open the free calculator

Check your eligibility automatically

EOBCheck's Full Report checks your bill against your Good Faith Estimate and tells you immediately whether you're at or above the $400 threshold — no manual math required.

See the Full Report — $9.99

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