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Military buyback calculator

Military buyback calculator

The military buyback calculator estimates the deposit you pay to count active-duty military service toward your FERS annuity, generally 3 percent of your military basic pay, then shows how much the added years could raise your yearly annuity. Interest may apply if you pay after the interest-free period.

The calculator

What the calculator shows

  • Your estimated deposit, before any interest.
  • An interest flag, if your interest-free period has passed.
  • The service the deposit adds, in years and months.
  • The yearly annuity the added service could add, at your high-3 and multiplier.
  • A simple payback count: how many years of the added annuity equal the deposit.

Your inputs

Prefilled with an example so the result is never empty. Change any number; the result updates as you type.

Educational estimate on the assumptions you entered

$2,430.00

deposit before any interest OPM charges

Want this run on your own records? A Federal Retirement Consultant (FRC®) checks the inputs with you, free.

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Rule
3% of military basic pay
Formula
$81,000 x 3%
Interest
Not included: it can apply when the deposit is paid later than OPM allows interest free
Where to start
Your agency HR office and form SF 3108

Assumptions behind this estimate

  • Basic pay is what you enter from your earnings statement.
  • No interest is included.
  • You are not receiving military retired pay, or you will waive it.
  • The added service is creditable under OPM's rules for your situation.

Educational estimate on the assumptions you entered, not a projection or a promise and not OPM's official computation. FFEBA is an education organization, not a financial advisor, and does not give personalized financial, tax or legal advice.

Inputs you will enter

  • Military basic pay by yearFrom the estimated earnings statement your branch's finance center provides. Basic pay only, no allowances.
  • Dates of active-duty serviceStart and end, or years and months.
  • Date you started FERS-covered civilian serviceFor the interest flag.
  • High-3 and expected multiplierTo show the annuity effect.

How we compute it

We multiply your military basic pay for each period by the deposit rate OPM applies to that period: 3 percent for most service, and higher rates for service performed in 1999 and 2000 (OPM CSRS/FERS Handbook, retrieved 2026-07-05). We total the periods for your deposit.

For the annuity effect, we multiply the added service by your high-3 and your multiplier, 1 percent or 1.1 percent (OPM, retrieved 2026-10-11). Dividing the deposit by that yearly figure gives a rough payback count in years. Interest, if any, is computed by your agency and OPM, so we flag it rather than estimate it.

A worked example

You served 4 years with total military basic pay of $100,000. The deposit is 3 percent, $3,000. At a $90,000 high-3 and 1 percent, 4 more years of service add $3,600 a year to your annuity, so the deposit equals less than one year of the added annuity. Educational estimate on the assumptions shown.

What to do with your result

Add the bought-back years to the FERS pension estimator and the retirement date finder, since paid military service can count toward eligibility too. The military buyback guide walks through the paperwork, and how the FERS annuity is calculated shows the formula in full.

FFEBA is an education organization. If you want someone to look at your own numbers, we can match you with a Federal Retirement Consultant (FRC), a professional trained on federal benefits. The FRC designation is listed with FINRA. The first review is free, nothing is booked until you choose a time, and you are never obligated to work with anyone we introduce. Get matched with an FRC.

Questions about this calculator

How much does a FERS military buyback cost?

For most active-duty service after 2000, the deposit is 3 percent of your total military basic pay. Service in 1999 and 2000 used slightly higher rates. Allowances and special pays are not included. Interest is added if you pay after the interest-free period.

Is the military buyback worth it?

It depends on your service, your high-3, your plans and any military retired pay. Each added year raises the annuity by 1 percent of high-3 (1.1 percent at 62 with 20 years). The calculator compares that with the deposit on your own numbers.

When do I have to pay the military deposit?

Under FERS, the deposit generally must be paid in full before you separate for retirement, or the military service does not count toward your annuity. Interest starts after an interest-free period that begins when you are first employed under FERS.

Do I get credit for military service if I receive military retired pay?

Usually only if you waive military retired pay, with limited exceptions such as certain disability-based retired pay. Check your situation with your HR office before paying a deposit.

Reviewed by the FFEBA education team. Last reviewed October 2026.

Sources

  1. U.S. Office of Personnel Management, CSRS/FERS Handbook (military service deposits), retrieved 2026-07-05
  2. U.S. Office of Personnel Management, FERS computation, retrieved 2026-10-11

Every government figure on this page carries its source and retrieval date. Worked examples are educational estimates on the assumptions shown, not a projection of any person's benefit. FFEBA is an education organization, not a financial advisor.

Keep reading

Read the rule behind the math.