Good Faith Estimate: The $400 Medical Bill Rule

If you were uninsured or chose not to use insurance for scheduled care, and a provider bills you at least $400 more than its Good Faith Estimate, you may be able to challenge that bill through a federal dispute process.

The $400 rule is not a cap on what a provider can charge. It is the point at which an eligible self-pay patient may get access to an independent review under the No Surprises Act.

The easiest way to figure out whether it applies to you is to check four things.

Does the $400 rule apply to you?

You may qualify if all four of these are true:

1. You did not use insurance for the care.
2. You received a written Good Faith Estimate before the service.
3. The bill from that provider or facility is at least $400 higher than its estimate.
4. The initial bill is dated within the last 120 calendar days.

That is the core test. CMS lays out the same requirements for its patient-provider dispute process.

Here is a simple hypothetical:

Meeting the threshold does not mean the provider automatically has to reduce the bill. It means you may qualify to have the dispute reviewed.

You can have insurance and still qualify

The Good Faith Estimate rules are not only for people without health insurance. They also apply when you have insurance but choose not to use it for the care. CMS calls this being self-pay.

That might happen because:

• the service is not covered by your plan;
• you want to compare the cash price with what you would pay using insurance; or
• you simply decide not to submit the service to your health plan.

CMS specifically says the protections apply when you do not have insurance or choose not to use it.

If the provider submitted the claim to your insurance plan, this particular $400 dispute process generally is not the right path. Your insurer’s appeal process or other No Surprises Act protections may apply instead.

Make sure you actually have a Good Faith Estimate

A phone quote is not the same thing as the written Good Faith Estimate you need for this dispute process.

A Good Faith Estimate is a written list of expected charges for scheduled health care. If you are not using insurance, providers generally must give you one when you schedule care at least 3 business days in advance or when you request an estimate before scheduling.

According to CMS:

• Schedule 3–9 business days ahead: you should generally get it within 1 business day.
• Schedule 10 or more business days ahead: you should generally get it within 3 business days.
• Ask before scheduling: the provider generally has 3 business days to give it to you.

You generally will not get a Good Faith Estimate for emergency care or for care scheduled only 0–2 business days ahead.

If you should have received an estimate but did not, you can complain to CMS. But there is an important limitation: CMS says you need the Good Faith Estimate to use the $400 dispute process.

So for planned self-pay care, get the number in writing and save it.

Compare the bill with the right estimate

This is probably the easiest part of the rule to get wrong.

A Good Faith Estimate currently covers expected charges from a single provider or facility. If several providers are involved in your care, you may receive separate estimates and separate bills.

For example, a procedure could involve a surgeon and a hospital. CMS recommends requesting an estimate from each.

So if the hospital estimated $2,000 and later billed you $2,450, that hospital bill is $450 above its estimate.

But you should not automatically combine a separate doctor’s bill with the hospital bill and compare the total with the hospital’s estimate.

Think provider by provider:

Estimate from Provider A → Bill from Provider A

That is the comparison that matters for the $400 test.

What should you do if you qualify?

If your situation passes the four checks, you can start the federal patient-provider dispute process through CMS.

You will generally need:

• your Good Faith Estimate;
• the bill you are disputing;
• the provider or facility’s contact information; and
• the current $25 non-refundable administrative fee.

You can start at the official CMS medical bill dispute page.

An independent third party reviews the dispute. The reviewer decides whether the higher charge is allowed under the process and what amount you should owe.

You can also continue talking with the provider while the dispute is underway. You and the provider are allowed to settle on a different amount before the review is finished.

One practical point: do not let the 120-day deadline disappear while you are going back and forth with the billing office.

What if the rule does not apply to you?

Not qualifying for the $400 process does not mean the bill is necessarily correct or that you have no options.

Your next move depends on what happened:

• No Good Faith Estimate? You may be able to submit a complaint to CMS.
• Used your insurance? Check your Explanation of Benefits and your plan’s appeal process.
• Bill looks wrong? Ask for an itemized bill and question the specific charge. You can read more about it here How to Negotiate a Hospital Bill
• Cannot afford the bill? Ask the provider about financial assistance, discounts or a payment plan.
• Difference is less than $400? You can still ask the provider to explain or reduce the bill; you just would not qualify for this federal process based on the $400 threshold.

CMS also has a medical-bill action-plan tool that can point you toward the right route based on your situation.

Before you self-pay, ask for this in writing

The Good Faith Estimate is most useful before the bill ever becomes a problem.

If you plan to pay for scheduled care without insurance, ask:

“I’m not using insurance for this service. Can you send me the Good Faith Estimate in writing, and tell me whether anyone else may bill me separately?”

Then keep the estimate.

Healthcare pricing is complicated enough without having to reconstruct a verbal quote months later. The written estimate gives you a number you can actually compare with the bill.

That is also the idea behind Unblind Health: seeing the information does not tell you which choice to make. It gives you the information to make the choice — and, in this case, potentially something to point back to if the bill changes.

Bottom line

The $400 rule is simpler than it sounds.

If you did not use insurance, have a written Good Faith Estimate, receive a bill from the same provider or facility that is at least $400 higher, and are still within 120 calendar days of the initial bill, you may qualify for the federal dispute process.

The rule does not guarantee that your bill will be reduced. But it gives eligible self-pay patients a formal way to challenge a bill that came in substantially above the written estimate.

Unblind Health provides general healthcare pricing and billing information for educational purposes. Individual costs and rights can vary based on insurance coverage, the services received, state law and other factors. Unblind Health does not provide medical, legal, insurance or financial advice.

Sources

Sources checked August 28, 2026.

• CMS — Dispute a medical bill
• CMS — Know your medical bill rights when not using insurance
• CMS — What is a Good Faith Estimate?
• CMS — Find an action plan for your medical bill