Insurance Denial Appeal Builder — Appeal Letter, Deadline and Checklist for a Denied Claim

Your insurance denied the claim. Here is the appeal, the deadline and what to attach.

Paste the text of your denial letter or explanation of benefits. The tool reads the denial reason, works out your appeal deadline, drafts the appeal letter, lists the evidence to gather for that kind of denial and gives you a calendar file with reminders before the deadline.

The text is read in this browser tab and never leaves your device. Dates are reminders computed from rules of thumb; the date on your notice controls. Not medical, legal or insurance advice.

1. The denial

Paste the denial letter or EOB text (optional, it fills in what it can read)

Reading is optional: you can fill the fields below by hand.

Type of plan

Denial reason

Date you received the notice

Days stated in the notice (optional)

Kind of appeal

Amount denied (optional)

2. For the letter

Your name

Insurer

Member ID

Claim number

Date of service

Provider

Service or treatment

Your phone

Why you needed it (in your own words, optional) If the deadline may have passed, why you could not appeal sooner (optional)

Fill what you know, then click Build my appeal.

How it works, and what it leaves out

Reading the denial: adjustment reason codes (CO-50, CO-197, CO-96 and others) and phrases such as "not medically necessary", "prior authorization", "out of network" or "investigational" are scored; the best match is suggested and the evidence for it is shown. You can change it.
Deadlines: 180 days for employer and individual plans, 60 for Medicare Advantage, 120 for Original Medicare, counted from the day you received the notice. Medicaid varies by state, so enter the days from your notice. A number in the notice always overrides these.
The letter: a first-person draft with the reason, a request for the criteria and claim file, and the documents to enclose for that kind of denial. It states no facts you did not give it.
Not checked: whether your plan covers the service, whether the denial is correct, state-specific rules, plan-specific deadlines shorter than the rule of thumb, and anything not in the text you pasted.
Unverified: the reason-code list and phrase matches come from public coding references and have not been tested on real denial letters from many insurers. If it misreads yours, change the reason by hand.

Common questions

How long do I have to appeal a health insurance denial?

For most employer and individual (Marketplace) plans the appeal window is at least 180 days from when you received the denial notice. Medicare Advantage plans commonly allow 60 days and Original Medicare 120 days for the first appeal. Medicaid deadlines vary by state. The date printed on your own notice is the one that counts, and this tool uses it when you enter it.

What should an insurance appeal letter include?

Your name and member ID, the claim number and date of service, the reason the plan gave, why the service was needed, a request for the clinical criteria and claim file the plan used, and the documents that support you, such as a letter from your clinician and your chart notes. The tool drafts all of this and lists what to gather for your denial reason.

What does CO-50 or CO-197 mean on my explanation of benefits?

These are standard adjustment reason codes. CO-50 is commonly defined as not medically necessary, CO-197 as missing prior authorization or precertification, CO-96 as a non-covered charge and CO-18 as a duplicate claim. Paste your denial text and the tool reads the codes and phrases to suggest the reason; check it against your paperwork.

Should I appeal or ask the doctor's office to fix the claim?

If the reason is a coding or billing problem, a missing authorization the provider can request after the fact, or a filing problem, call the provider's billing office first; a corrected claim is often faster than an appeal. If the plan decided the service was not necessary, excluded or experimental, an appeal with clinical support is the route.

What happens if my appeal is denied?

For most commercial plans you can ask for an independent external review, generally within four months of the final internal denial. Medicare and Medicaid have their own next levels. The tool shows the next step for your plan type.

Does this tool give legal or medical advice?

No. It drafts a letter and computes reminder dates from rules of thumb. It does not know your plan's terms, and it cannot promise that an appeal succeeds. You are responsible for checking every date and statement before you send anything.

Is my denial letter uploaded anywhere?

No. The text is read in this browser tab and never leaves your device. There are no accounts, cookies or analytics vendors. A denial letter contains health information, which is why nothing is sent to a server.