Free Calculator
Military Service Buyback Calculator
FERS employees: estimate what it costs to buy back your military service time, the pension boost it adds, and how quickly the deposit pays for itself. Private by design — every calculation happens on your device.
Break-even point
Deposit cost
Pension boost
Important considerations this tool does not fully model
- The deposit must be paid in full before you retire — no extensions.
- Bought-back time also counts toward retirement eligibility and your high-3 service — not just the dollar boost.
- If you already receive military retired pay, you generally must waive it to get FERS credit for that service (narrow exceptions for disability/reserve retirement). This can be a major factor — confirm before paying.
- Bought-back service does not count toward the FERS Special Retirement Supplement.
- Earlier payment means less interest — this is usually time-sensitive.
How this works
The deposit. For FERS, buying back military service costs 3% of your total military basic pay (base pay only — excluding BAH, BAS, allowances, and combat pay).
Interest. There's an interest-free grace period of about 2 years from your FERS hire date. After that, interest compounds annually on the unpaid balance at a rate OPM sets each year (4.25% for 2026). This tool uses a simplified annual-compounding estimate; OPM's actual calculation uses yearly rate variations and a specific compounding date.
The pension boost. Each bought-back year adds to your FERS annuity via the standard formula: high-3 × years × multiplier (1.0%, or 1.1% if you retire at 62+ with 20+ years).
Break-even. Dividing the total deposit by the annual pension increase tells you how many years of retirement it takes to recoup the cost. A small break-even (a few years) usually signals a strong buyback.
References: OPM — FERS Information and your branch's DFAS military service deposit process.