Health Insurance Premium Calculator Formula

Understand the math behind the health insurance premium calculator. Each variable explained with a worked example.

Formulas Used

Total Annual Cost

total_annual_cost = annual_premiums + oop_costs

Annual Premiums

premium_total = annual_premiums

Your Medical Cost Share

your_medical_share = oop_costs

Variables

VariableDescriptionDefault
monthly_premiumMonthly Premium(USD)450
annual_deductibleAnnual Deductible(USD)2000
coinsurance_rateCoinsurance (Your Share)(%)20
expected_medicalExpected Annual Medical Bills(USD)5000
out_of_pocket_maxOut-of-Pocket Maximum(USD)8000
annual_premiumsDerived value= monthly_premium * 12calculated
after_deductibleDerived value= max(expected_medical - annual_deductible, 0)calculated
coinsurance_costDerived value= after_deductible * coinsurance_rate / 100calculated
oop_costsDerived value= min(min(expected_medical, annual_deductible) + coinsurance_cost, out_of_pocket_max)calculated

How It Works

Understanding Health Insurance Costs

Your total health insurance cost includes:

1. Premiums: Fixed monthly payments regardless of care used 2. Deductible: Amount you pay before insurance kicks in 3. Coinsurance: Your percentage share after meeting the deductible 4. Out-of-pocket maximum: Annual cap on your total spending

Total Cost = Annual Premiums + min(Deductible + Coinsurance, OOP Max)

Worked Example

$450/month premium, $2,000 deductible, 20% coinsurance, $5,000 expected bills.

monthly_premium = 450annual_deductible = 2000coinsurance_rate = 20expected_medical = 5000out_of_pocket_max = 8000
  1. 01Annual premiums = $450 x 12 = $5,400
  2. 02You pay first $2,000 (deductible)
  3. 03Remaining $3,000 x 20% = $600 coinsurance
  4. 04Out-of-pocket = $2,000 + $600 = $2,600
  5. 05Total annual cost = $5,400 + $2,600 = $8,000