Medical Bill Cost Calculator: Estimate What You Owe (Free)

By Qamar S, 15 years in US medical billing · Last reviewed September 26, 2026

Use this free calculator to estimate your share of a medical bill before you pay it. Enter the numbers from your insurance plan and your Explanation of Benefits, and it shows how much goes to your deductible, your coinsurance and your insurer.

What will I pay for this medical service?

Allowed amount for the service ($)From your EOB or your insurer’s cost estimator. Not the hospital’s full charge.

Copay for this service ($)Enter 0 if this service uses deductible and coinsurance instead.

Yearly deductible ($)

Deductible already met this year ($)

Your coinsurance (%)Often 20% or 30%.

Out-of-pocket maximum ($)2027 limit for ACA plans: $12,000 per person.

Out-of-pocket already spent this year ($)Include deductible, copays and coinsurance you’ve paid.

How the calculator works

If the service has a copay, you pay the copay and your insurer pays the rest.
Otherwise, you pay the allowed amount until your deductible is met.
After that, you pay your coinsurance percentage and your insurer pays the rest.
Your total for the year can’t go over your out-of-pocket maximum. For 2027, ACA plans can’t set it above $12,000 for one person or $24,000 for a family.

From 15 years in billing: always use the allowed amount from your EOB, not the “charges” line on the hospital bill. The charge is the list price, and using it makes your estimate look far worse than it is.

Want to understand each term? Read deductible vs copay vs coinsurance and what is an EOB. Think your bill is wrong? Get the free hospital bill audit checklist.

Cite or share this tool: link to https://medbillguide.com/tools/medical-bill-calculator/

This tool gives estimates for education only. It is not legal, financial or insurance advice. See our Disclaimer.