Military to Federal Civilian: FERS, Buyback and TSP Guide

If you move from military service into a federal civilian job covered by FERS, treat your retirement as three separate decisions: whether prior active-duty service is creditable, whether to pay a military service deposit, and how your civilian FERS pension and TSP fit beside any military retired pay. A deposit can be valuable, but it is not automatically the right choice for every veteran or retiree.

This guide explains the standard FERS rules using current Office of Personnel Management (OPM), Internal Revenue Service (IRS), and Thrift Savings Plan guidance. It is general education, not an individual benefit determination. Ask your agency benefits office for a written estimate before paying a deposit, waiving retired pay, or choosing a retirement date.

Military-to-federal retirement: the short answer

• Your civilian FERS pension is based primarily on your creditable service and high-3 average pay. The standard multiplier is 1%; it becomes 1.1% only when you separate for retirement at age 62 or older with at least 20 years of creditable service.
• Post-1956 military service generally requires a deposit before separation from federal employment to count under FERS. Most periods use 3% of military basic pay, plus any applicable interest.
• Military retired pay changes the analysis. Most regular military retirees cannot use the same service in a FERS computation unless they waive military retired pay, but OPM lists exceptions for certain combat-related disability retirement and reserve-component retirement under 10 U.S.C. chapter 1223.
• The FERS annuity supplement is not automatic and does not equal your entire projected Social Security check. Eligibility depends on the type and timing of retirement, and OPM uses a prorated computation.
• Military and civilian TSP participation share one annual elective-deferral limit. For 2026, that limit is $24,500, with separate catch-up rules for eligible participants.

How the standard FERS pension is calculated

For most regular FERS employees, the unreduced annual basic annuity starts with one of these formulas:

• Under age 62 at separation, or age 62 with fewer than 20 years: 1% × high-3 average pay × years and months of creditable service.
• Age 62 or older at separation with at least 20 years: 1.1% × high-3 average pay × years and months of creditable service.

For example, 25 years and a $120,000 high-3 produces a $30,000 annual basic annuity under the 1% formula. If the employee separates at age 62 or later with those 25 years, the 1.1% formula produces $33,000. These are gross illustrations before survivor-election costs, age reductions, insurance premiums, taxes, court orders, or other adjustments.

Special-category employees, CSRS-component service, disability retirement, and other situations use different rules. Confirm the governing formula with your benefits office and OPM’s official FERS computation guidance.

When an immediate FERS retirement is available

For a regular employee, the standard combinations for an unreduced immediate retirement are:

• Minimum Retirement Age (MRA) with at least 30 years;
• age 60 with at least 20 years; or
• age 62 with at least five years.

MRA ranges from age 55 to 57 based on birth year; it is 57 for people born in 1970 or later. MRA+10 can permit retirement with at least 10 years, but the annuity is generally reduced by 5% for each year it begins before age 62. Postponing the start may reduce or eliminate that age reduction. Early, discontinued-service, special-category, deferred, and disability retirements have separate conditions.

Use OPM’s types of FERS retirement rather than choosing a date from a calculator alone.

What a military service deposit does

A military service deposit—often called a military buyback—is a payment that can make qualifying military service creditable under FERS. For military service after 1956, OPM lists these deposit rates:

• 3% of military basic pay for service through 1998;
• 3.25% for service during 1999;
• 3.4% for service during 2000; and
• 3% for service from 2001 to the present.

The calculation uses military basic pay, not total compensation with housing or subsistence allowances. Interest may apply. OPM describes an initial two-year interest-free period, with interest assessed later under its annual rules; the timing can vary with the employee’s coverage and return from military duty. Starting early gives the agency time to obtain military earnings and correct records, but “pay within two years or lose eligibility” is incorrect.

The deposit must generally be completed through the employing agency before separation for the service to count under FERS. Follow OPM’s military service-credit instructions and your agency’s process.

Does bought-back military time affect both eligibility and pension amount?

Qualifying deposited military service can affect creditable service used for retirement eligibility and the annuity computation. That does not mean every period counts in every scenario. Academy time, reserve duty, active-duty periods, USERRA-covered absences, retired-pay status, and service already used for another benefit can require different documentation and analysis.

A useful illustration is an employee with eight potentially creditable military years and 22 civilian years. If the agency determines all eight years are creditable and the required deposit is completed, the employee may have 30 years for applicable FERS purposes. The high-3 is still based on covered civilian basic pay—not the prior military salary.

Do not estimate the deposit from rank alone. Request the official military earnings record and a deposit calculation from your employing agency.

Military retirees: when a waiver may be required

Receiving military retired pay does not prevent you from earning a separate FERS benefit from your later civilian service. The important question is whether the military years themselves can also be credited in the FERS annuity.

OPM says a person receiving military retired pay generally cannot receive FERS credit for that military service unless the retired pay was awarded:

• for a qualifying service-connected disability incurred in combat or caused by an instrumentality of war during a period of war; or
• under 10 U.S.C. chapter 1223 for reserve-component retirement.

Outside an exception, the employee may elect to waive military retired pay and pay the required deposit to use the service under FERS. That is a major, individual decision—not a step this article recommends. Compare the lifetime value, survivor consequences, cost-of-living treatment, taxes, and timing of both benefits. OPM directs employees considering a waiver to contact the retired-pay center before retirement; see its military retired pay guidance.

How to compare a military deposit responsibly

Ignore generic claims that a buyback produces a guaranteed 20× or 40× return. A useful comparison needs your actual deposit and benefit estimates:

1. Get the official deposit amount. Include applicable interest and confirm which service periods qualify.
2. Request two annuity estimates. Ask for one with the military service and one without it, using the same retirement date and survivor election.
3. Check eligibility effects. Determine whether the service changes your first unreduced retirement date or only the pension amount.
4. Account for retired pay. If a waiver would be required, compare the benefit you would surrender—not merely the deposit cost.
5. Test longevity and alternatives. Calculate a break-even period and compare the deposit with other uses of the money without assuming investment returns.

A simplified illustration: if an accepted deposit adds five years to a FERS computation with a $100,000 high-3, those years add $5,000 annually under the 1% formula. That does not prove the decision is favorable; the actual deposit, interest, retirement date, survivor reduction, taxes, and any retired-pay waiver still matter.

The FERS annuity supplement: what it is and who may receive it

The retiree annuity supplement is a temporary FERS benefit intended to approximate the Social Security value earned during FERS-covered service. It ends at age 62. It does not continue until the person claims Social Security, and it is not simply the person’s full age-62 Social Security estimate.

OPM’s standard eligibility categories include employees who retire with an immediate annuity at MRA with 30 years, at age 60 with 20 years, or under certain early/special provisions. MRA+10, deferred, and disability retirees generally do not qualify. At least one full calendar year of FERS-covered service is required for the computation.

The estimate broadly prorates an age-62 Social Security amount for years of FERS service, subject to OPM’s detailed rules. Military deposit service does not automatically become FERS-covered civilian service in that supplement calculation. The supplement is also subject to an earnings test after MRA. Ask the agency for an official estimate and use OPM’s retiree annuity supplement handbook chapter for the governing details.

TSP after moving from military to federal civilian employment

The TSP can contain uniformed-services and civilian balances under the same participant account, but contribution sources and matching rules remain distinct. For eligible FERS employees, the agency generally contributes 1% automatically and provides matching that can bring total agency contributions to 5% when the employee contributes at least 5% of basic pay. Confirm eligibility and vesting rules in your appointment documents and the TSP contribution guidance.

The IRS says the 2026 elective-deferral limit that includes TSP contributions is $24,500. The general age-50 catch-up limit is $8,000, while eligible participants ages 60–63 can have a higher $11,250 catch-up limit. These limits can change annually.

If you contribute to both a uniformed-services TSP and a civilian TSP during the same calendar year, coordinate payroll elections so combined elective deferrals do not exceed the limit. Combat-zone tax-exempt contributions and annual-additions rules can add complexity; ask TSP or a qualified tax professional about your facts.

A practical military-to-federal checklist

1. Confirm retirement coverage. Verify that the appointment is covered by FERS and note the service computation dates used for leave and retirement; they are not always identical.
2. Collect records. Keep DD Form 214 documents, orders, military earnings records, civilian SF-50s, and prior retirement-coverage records.
3. Ask HR which military periods may be creditable. Get the answer in writing and identify any retired-pay issue.
4. Request the formal deposit calculation. Do this early enough to resolve missing earnings and avoid unnecessary interest.
5. Compare written estimates. Review annuities and retirement dates with and without the deposit.
6. Coordinate TSP contributions. Capture any available agency match while staying within the combined annual limit.
7. Review FEHB and survivor requirements. A pension estimate alone does not show whether health-insurance continuation or survivor elections are available.
8. Recheck before separation. Deposits generally must be completed before leaving the agency, and a retired-pay waiver requires advance coordination.

Common mistakes to avoid

• Assuming every veteran should buy back every year.
• Using total military compensation instead of basic pay to estimate a deposit.
• Believing the deposit must be paid within two years rather than understanding the interest schedule and final deadline.
• Assuming reserve retired pay always requires a waiver.
• Treating bought-back military service as FERS-covered service for every annuity-supplement calculation.
• Adding separate military and civilian TSP elective-deferral limits.
• Choosing a retirement date from an app without an agency benefits estimate.

Use a calculator as a planning tool—not a benefit determination

A calculator can compare high-3, service, retirement-age, deposit, and TSP scenarios, but OPM and your employing agency determine the actual benefit. Our FERS Pro calculator for iPhone can help organize scenarios before you request written estimates. The link promotes an app published by our organization; it does not replace OPM or agency counseling.

Official sources

• OPM: FERS computation
• OPM: Types of FERS retirement
• OPM: Service credit and military deposits
• OPM: Military retired pay and FERS credit
• OPM: Retiree annuity supplement handbook
• IRS: 2026 elective-deferral and catch-up limits