Health Insurance Deductible Calculator
Shows exactly how much you will pay out of pocket for a given level of medical expenses, accounting for your annual deductible and coinsurance rate. Use it during open enrollment to compare plan tiers or to budget for a planned procedure.
About this calculator
Your out-of-pocket cost depends on whether your medical expenses exceed your annual deductible. The formula has two cases: if medical_expenses ≤ annual_deductible, you pay 100% of the bill (your insurer pays nothing yet). Once expenses exceed the deductible, you pay the full deductible plus a coinsurance percentage of the remaining amount: out_of_pocket = annual_deductible + (medical_expenses − annual_deductible) × (coinsurance / 100). Coinsurance is the cost-sharing percentage you owe after the deductible is met — typically 20–30% on most employer plans. This continues until you reach your plan's out-of-pocket maximum, at which point insurance covers 100%. Understanding this split is critical when comparing a low-premium, high-deductible plan (HDHP) against a higher-premium, lower-deductible PPO, since the right choice depends heavily on your expected annual medical spending.
How to use
Suppose your annual deductible is $1,500, you expect $4,000 in medical expenses, and your coinsurance rate is 20%. Step 1 — check threshold: $4,000 > $1,500, so the second formula applies. Step 2 — excess over deductible: $4,000 − $1,500 = $2,500. Step 3 — coinsurance portion: $2,500 × 0.20 = $500. Step 4 — total out-of-pocket: $1,500 + $500 = $2,000. Your insurer covers the remaining $2,000. If your expenses had been only $1,200, you would pay the full $1,200 with zero insurer contribution that year.
Frequently asked questions
What is the difference between a deductible and coinsurance in health insurance?
A deductible is a fixed dollar amount you must pay entirely on your own before insurance begins sharing costs. Coinsurance is the percentage of costs you continue to share with your insurer after the deductible is met. For example, with a $1,000 deductible and 20% coinsurance, you pay $1,000 up front, then 20 cents of every dollar thereafter. Both mechanisms exist to discourage overuse of medical services and to keep premiums lower by transferring some risk to the insured. Most plans also have an out-of-pocket maximum that caps your total annual exposure.
When does it make sense to choose a high-deductible health plan?
An HDHP makes financial sense if you are generally healthy, rarely use medical services, and want lower monthly premiums. The premium savings can be invested in a Health Savings Account (HSA), which offers triple tax advantages. However, if you have chronic conditions, take expensive medications, or anticipate surgery, a lower-deductible plan often costs less in total even though premiums are higher. The break-even point is where the premium difference equals the deductible difference — use this calculator to model both scenarios with your expected expenses.
How do I calculate my total out-of-pocket costs for a year with health insurance?
Start with any expenses below your deductible — you pay 100% of those. For expenses above the deductible, multiply the excess by your coinsurance rate and add the deductible. Continue adding coinsurance amounts until you hit your plan's out-of-pocket maximum, after which your share drops to zero. Don't forget to include copays for office visits and prescriptions, which are separate from deductibles on many plans. Summing these components over your expected annual utilization gives a realistic total cost estimate that you can compare across plan options.