Medicare Part B Late Enrollment Penalty Calculator
Estimate the added Part B premium caused by delayed enrollment.
Last updated: October 15, 2026
Estimated penalty over selected period
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- Monthly penalty: —
- Monthly premium including penalty: —
- Base premium over period: —
On this page
Quick summary: Estimate the added Part B premium caused by delayed enrollment.
Read the method, example and limitations
Updated reference sections in this guide are in English.
Guide language: English. Updated October 15, 2026.
What this calculator estimates
Medicare Part B Late Enrollment Penalty Calculator
Inputs and units
Use the units shown for Current standard monthly Part B premium ($), Full 12-month periods late, Penalty per full year (%), Months premiums are paid, Covered people with the penalty. Required fields cannot be blank. Use zero only where that field and the model allow it. Select Calculate after changing a scenario.
Method and assumptions
Use a 10% premium increase for each full 12-month period late. Round each person's combined standard premium plus penalty to the nearest ten cents. The incremental penalty is that rounded amount less the standard premium. Multiply by people and months. The prefilled standard premium is 202.90 for 2026.
Worked example
Two full late years with the 2026 standard premium produce 243.50 monthly after rounding. The extra 40.60 monthly is 487.20 over twelve months for one person.
Limitations
This illustration holds the premium constant over the selected months. Actual premiums change by year. Special enrollment periods, qualifying coverage and Medicare Savings Programs may remove a penalty; SSA determines the eligible late periods. IRMAA is separate.