Military Service Buyback for FERS: The Math Behind Adding Years to Your Pension

Who This Article Is For

• FERS employees who served in the U.S. military and have not yet made the OPM deposit
• Federal employees trying to understand whether a military buyback pencils out financially
• Employees approaching retirement who want to verify their creditable service total before submitting paperwork
• Employees who served in the National Guard or Reserve and are unsure what counts
• HR Benefits specialists advising employees on creditable service questions

Should You Do the Military Buyback? A Quick Decision Guide

The deposit pencils out for most FERS employees — but not all. Here's a fast filter before diving into the math.

For the majority of FERS employees with qualifying active-duty service, the decision is straightforward. The deposit is small; the lifetime pension increase is large; the break-even is typically under 18 months of retirement. The rest of this article explains the math in detail so you can verify it for your specific situation.

What the Military Service Buyback Is — and Is Not

When you separate from the military and enter federal civilian service, your military years do not automatically count toward your FERS pension. They exist in a separate record at DFAS. Without action on your part, OPM treats your federal career as beginning on your first day of civilian employment — and your pension is calculated on civilian service alone.

The military service buyback — formally called a military deposit under 5 U.S.C. § 8411(c) — is the mechanism for changing that. By making a deposit to OPM equal to a percentage of your military basic pay, you convert that service into FERS creditable service that counts the same as civilian years in the pension formula.

It is a one-time deposit. Once made, those years are permanently added to your service history. You do not continue paying into a separate fund. The deposit buys the service credit, and the service credit raises your pension for life.

The buyback does not affect your TSP, your FEHB eligibility, or your Social Security record. Its effect is specific: it adds years to your FERS creditable service total, which raises your annuity through the standard FERS pension formula.

Who Qualifies — and What Counts

Service that qualifies

Source: OPM FERS Handbook Ch. 20; 5 U.S.C. § 8411(c); 5 CFR § 842.304

Discharge requirement

Your DD-214 (Certificate of Release or Discharge from Active Duty) must show an honorable discharge or a discharge under honorable conditions (general discharge). An other-than-honorable, bad conduct, or dishonorable discharge does not qualify. If your discharge characterization is in question, contact your branch's discharge review board before assuming eligibility.

Service before and after civilian employment

The buyback applies to military service at any point in your life relative to civilian employment — whether you served before entering federal service, between periods of federal service, or in rare cases during a break in civilian employment. What matters is the nature of the service (active duty) and the type of discharge — not the sequence relative to your civilian career.

The Deposit Formula: What It Actually Costs

The deposit is calculated as a percentage of your military basic pay — not total compensation, not allowances, not special pay.

What "military basic pay" means for this calculation: The base pay shown on your Leave and Earnings Statements (LES) for the service period — not BAH, BAS, hazardous duty pay, or other allowances. DFAS maintains records of this and provides the exact figures when you request your earnings history.

Why the deposit is almost always small

Military basic pay, particularly for enlisted personnel in their first enlistment, is modest. At 3%, the deposit on four years of E-4/E-5 service is often under $3,000 before interest — a number that produces a permanent lifetime pension increase worth 10–20 times that amount.

The table below illustrates approximate deposit amounts based on typical enlisted and junior officer pay scales. These are illustrative ranges only — actual deposit amounts depend on your exact pay grade, years of service at each grade, and the period when you served.

Approximate ranges only based on published DoD pay tables. Actual basic pay depends on grade, time-in-grade at each step, special pays excluded. Request your exact earnings history from DFAS using Form RI 20-97.

These principal amounts do not include interest. If you have been in federal civilian employment for more than two years without making the deposit, interest has been accruing — see the Interest section below.

The Break-Even Analysis: A GS-13 Example

The financial case for the buyback is unusually clear-cut compared to most retirement decisions. The deposit is small and one-time; the pension increase is permanent and cumulative.

Profile used throughout this article:

Illustrative example only. Figures use a hypothetical FERS employee profile. Actual deposit costs, pension amounts, and break-even ages depend on your military earnings history, civilian High-3, years of service, and OPM determinations at retirement.

• Current age: 45
• Military service: 4 years (E-5, separated at 26, honorable discharge)
• Civilian service to date: 19 years
• Estimated High-3 at retirement: $112,000
• Target retirement age: 57 (12 more years)
• MRA: 57 (born after 1969)

Without the buyback

At age 57 with 31 years of civilian service:

With the buyback (4 years added)

At age 57 with 31 civilian + 4 military = 35 years total creditable service:

The net difference

Supplement comparison applies only for ages 57–61. Over 5 years, the supplement differential adds ~$10,800 before the supplement ends at 62. The pension differential of $374/mo is permanent and lifetime.

Break-even

Assuming a deposit principal of approximately $2,800 (4 years E-5, 2005–2009) plus interest of approximately $2,200 after 17 years of accrual at blended OPM rates:

Deposit estimate for illustrative purposes. Your actual deposit will be calculated from DFAS earnings records by your agency HR office — request verification before making any financial decision.

The break-even improves further when you account for COLA adjustments on the additional pension amount, the supplement differential in the first five years of retirement, and the reduction in principal you'd have paid if the deposit had been made earlier (before interest compounded).

Quick Reference: How Much Does Military Buyback Add to Your Pension?

The FERS pension formula is High-3 × Years of Service × 1%. Every military year you buy back adds directly to that "Years of Service" figure. The table below shows the annual pension increase for common combinations of military service and High-3 salary — before any supplement or early-retirement considerations.

Uses standard 1% FERS multiplier. Employees retiring at 62+ with 20+ years qualify for the 1.1% multiplier — multiply these figures by 1.1 for that scenario. Amounts are gross before taxes. See the FERS Pension Calculator to model your specific numbers including retirement age and service history.

These increases are permanent and lifetime. They also receive the same annual COLA adjustments as the rest of your FERS annuity. A $400/month increase at age 57 is not $400/month for a few years — it is $400/month (COLA-adjusted) for the rest of your life.

The Hidden Multiplier: FERS Supplement Eligibility

The pension increase is the obvious financial case for the buyback. The FERS Supplement impact is the one most employees miss — and in some scenarios, it's the larger benefit.

The FERS Supplement is a monthly payment made by OPM from your retirement date until age 62, designed to bridge the gap between early federal retirement and Social Security eligibility. It is available to employees who retire at their MRA with 30 or more years of creditable service.

If your civilian service alone puts you at 27 or 28 years at your MRA, you would not ordinarily qualify for an immediate retirement with full supplement eligibility at MRA. Military buyback years count toward that threshold.

For an employee whose military service is the difference between qualifying and not qualifying for the supplement, the buyback unlocks five years of payments at $1,200–$1,600/month — $72,000–$96,000 in additional retirement income — in addition to the permanent pension increase. The supplement calculation uses your total creditable service (civilian + military) for the numerator: (total years ÷ 40) × estimated SS benefit at 62. For a full breakdown of how the supplement is calculated and when it ends, see FERS Supplement Explained.

The supplement also affects when you can retire. An employee who needs 30 years to retire at MRA without penalty can reach that threshold 2–4 years earlier by counting military service. That earlier retirement date may be worth more than any financial calculation captures — but the numbers alone typically justify the deposit.

For a full explanation of how the supplement works, who qualifies, and how to plan for the income cliff at 62, see FERS Supplement Explained.

Interest: Why Waiting Makes This More Expensive

The deposit is not frozen at the original 3% figure. Interest accrues on the unpaid balance beginning two years after your first day of federal civilian employment.

The interest accrual rule:

OPM publishes the applicable interest rate each calendar year. Rates have ranged from approximately 2% to 8% over the past two decades, with recent rates in the 4–6% range. Interest compounds annually — not daily or monthly — on January 1 of each year.

What this means in practice: An employee who joins federal service at 26 and serves 25 years before checking on the buyback at 51 has been accruing interest on their deposit principal for 23 years. At a blended average rate of 4%, the accrued interest nearly doubles the original deposit cost.

The practical implication: The break-even analysis above is most favorable when you make the deposit early. An employee who makes the deposit in year 1 or 2 of federal service pays exactly the 3% principal. An employee who waits until age 50 may pay two to three times the original principal. The pension increase is the same in both cases — only the cost differs.

If you served in the military and entered federal civilian service within the last two years: make this deposit now. The window before interest begins accruing is the optimal time to act. After that window, the case is still strong — but it becomes slightly less compelling with each passing year.

How to Make the Deposit: Step-by-Step

Processing timeline to expect: From DFAS request to final payment, allow 3–6 months if no complications arise. If you're within two to three years of your target retirement date, initiate the process now. Do not wait until the year before retirement — agencies and DFAS can be slow, and the deposit must be posted before your retirement paperwork is final.

The Deadline — and Why It Is Absolute

The military service deposit must be completed before your retirement becomes final. Under 5 U.S.C. § 8411(c)(2), OPM does not accept deposits after the retirement date.

"Before retirement is final" means before OPM processes your retirement application and issues your initial annuity. In practice, this generally means before your agency submits your retirement package to OPM — which happens shortly after your separation date.

If you are planning to retire in the next 12–24 months and have military service you have not yet made a deposit for, treat initiating the DFAS request as a priority task — not a later consideration.

Military Retired Pay: The Exception That Trips People Up

Employees who served a full military career (typically 20+ years) and are receiving military retired pay face a different set of rules than those who separated before retirement eligibility.

The general rule: If you are receiving military retired pay, you cannot also receive FERS pension credit for those same years without waiving the retired pay. The same service cannot generate income from two federal sources simultaneously — this is the dual compensation restriction under 5 U.S.C. § 3323.

What "waiving military retired pay" means: You formally request that DFAS stop paying your military retirement. In exchange, your OPM pension is calculated on your total years — military plus civilian. This makes sense financially only when your FERS pension (calculated on all service) exceeds the combined value of your military retired pay plus a smaller FERS pension (calculated on civilian service only).

For employees receiving military retired pay based on length of service (not disability), the waiver decision requires running the actual numbers — the analysis depends on your military retirement amount, your expected FERS pension on combined service, and how many years you project to live in retirement. This is one scenario where a fee-only financial advisor with federal benefits expertise is genuinely worth the cost.

For the majority of employees this article is written for — those who separated from the military before reaching retirement eligibility and are now in federal civilian service — the dual compensation question does not apply. If you served 4–8 years and separated with an honorable discharge, you are receiving no military retired pay and the buyback is straightforward.

What Does Not Count: Reserve and Guard Drill Time

This is the most common source of confusion about the buyback, and the answer is unambiguous: weekend drill periods, annual training (AT), and other non-continuous Reserve or National Guard service do not count toward FERS creditable service and cannot be bought back.

What counts for Reserve and Guard members is only the periods spent on continuous active duty orders — typically deployments, extended mobilizations, or periods of full-time active duty under Title 10 (federal orders) or equivalent. A weekend drill is compensated by the military and appears in pay records, but it is not the type of service that 5 U.S.C. § 8411(c) makes creditable.

The practical test: If the service was on full-time, continuous active duty orders — meaning you were away from civilian employment for the duration — it likely qualifies. If it was reserve component service where you showed up on weekends and occasional weeks, it does not. Your DFAS earnings statement will show the periods and amounts. Your agency HR office will identify which periods qualify under OPM guidelines.

Reservists and Guard members who were called to extended active duty for deployments (particularly common for post-9/11 mobilizations) frequently have substantial periods of qualifying continuous active duty service mixed in with non-qualifying drill time. DFAS separates these out in the earnings statement.

Common Mistakes

Decision Framework: Five Questions to Answer Before You Proceed

For most FERS employees with qualifying military service, the answer to "should I do this?" is almost always yes. The deposit-to-pension-increase ratio is more favorable than any other financial transaction available in the federal benefits landscape. The main exception is employees receiving length-of-service military retired pay who would need to waive it — that analysis is more complex and more individual.

The FedHorizon Retirement Report models your creditable service total — civilian plus military — across retirement ages and shows how each year of added service changes your monthly pension and supplement eligibility. To see how retirement timing interacts with total service, see Retire at 57 vs. 62: The Actual Numbers for FERS Employees.

FedHorizon is a decision-support tool, not a financial advisor or legal service. Military service deposit eligibility, qualifying service determination, and deposit calculations are governed by OPM regulations and must be verified with your agency HR Benefits office and DFAS. Employees receiving military retired pay should consult a federal benefits attorney or fee-only financial advisor before making waiver decisions.

Frequently Asked Questions