Civilian Deposit and Redeposit Calculator

How this is calculated

There are two ways federal civilian service ends up not counting. Either no retirement deductions were ever taken from your pay — a temporary, term, indefinite or intermittent appointment — or deductions were taken and then refunded to you when you left. The first is bought back with a deposit, the second with a redeposit, and the two are billed as separate accounts even when one application covers both.

The arithmetic is in three parts: what the principal is, what the interest has done to it, and — the part most calculators leave out — which of seven rules decides what happens if you simply never pay.

The principal

deposit   = basic pay earned × the deduction rate in force at the time
redeposit = the refund you were paid

Under FERS the deposit rate is a flat 1.3%of basic pay. The handbook is explicit that this applies “regardless of when the service was performed or whether deductions would have been taken at 1.3 percent” — it is not the FERS contribution rate, and matching it to one is a common error.

Under CSRS the deposit is what would actually have been withheld, so it follows the contribution rate of the day:

Law enforcement and firefighter service after 1974 adds 0.5% to whichever rate applies. The 1999 and 2000 bump is the same temporary increase in employee contributions the military deposit carries, and is real rather than a transcription error.

Because the rate and the crediting rule both change on dates, the tool splits the period of service wherever either one does, and apportions the pay across the pieces by length. That split is required rather than decorative: OPM runs two separate interest computations for CSRS service spanning 1 October 1982, and a FERS period spanning 1 January 1989 has one half that can be bought and one half that cannot. Spreading a single pay figure evenly across the period is this tool’s one modelling assumption— your agency works from the real pay history, so its figure will differ a little.

The interest

Nothing like the military deposit except the rate table, which is the same Treasury schedule:

• It posts on 31 December, at that calendar year’s single rate, on the whole unpaid balance, and compounds.
• It starts at the midpoint of the service for a deposit, or on the date the refund was paid for a redeposit.
• There is no grace period. A military deposit gives a newly hired veteran three years before a dollar is charged. A civilian deposit begins compounding in the middle of the service itself, which is why balances from the 1980s now run to several times their principal.
• 4% through 1947, 3% from 1948 through 1984, then the Treasury’s variable rate — 4.25% for 2026. The implementation is asserted against the rate table printed in chapter 21 itself.

Two mechanical rules follow from “once a year, on 31 December”, and the tool models both. Principal that enters partway through a year is charged only for the remainder of that year. And a year in which the balance is paid in full carries nointerest at all, rather than a part year — so paying on 31 December is free, and paying on 1 January costs a whole year.

What happens if you never pay

This is the part that decides whether paying is worth it, and it is not one rule but seven. Two of them invert the intuition: a CSRS employee with pre-1982 deposit service already has the credit and is buying the removal of a penalty, while a FERS employee with post-1988 non-deduction service is refused outright however much they are willing to pay.

The FERS redeposit is the newest of these and the one most often reported wrongly. Until 28 October 2009 a FERS refund was a permanent forfeiture: the service could not be repaid and counted for nothing. Section 1904 of Public Law 111-84 (PDF) created it, for employees covered by FERS on or after that date whose separation also falls on or after it. Advice written before then is out of date, and a good deal written since has not caught up.

What paying it buys

added annuity = high-3 × the accrual factor × years credited
payback     = balance owed ÷ added annuity

FERS credits bought service at 1% of high-3 a year, or 1.1% at 62 with 20 years. CSRS credits it at 2%, because service bought back is service added to a career: unless the whole career runs under ten years, the added years land in the top bracket. The payback figure is stated before tax, before cost-of-living adjustments and before any survivor reduction, all three of which move it.

What this does not model

• The actuarial reduction itself, for an unpaid CSRS redeposit covering service that ended before October 1990. OPM computes it from present-value factors that vary by age at retirement and are revised in the Federal Register. The tool prints the balance the reduction would be based on and names the rule, rather than carrying a factor table it cannot keep current.
• The alternative form of annuity, under which a deposit or redeposit can be deemed paid out of a lump sum. Eligibility for it is narrow, and it is a separate decision from this one.
• Instalment plans. The tool computes one balance paid in full on one date. Paying by allotment reduces the balance as you go, so the interest comes out lower than shown.
• Peace Corps and VISTA volunteer service.A service credit payment with its own rules — 7% of the readjustment allowance under CSRS, 3% under FERS, and a two-year interest-free grace period no other civilian deposit gets.
• Which of two computations OPM applies to a FERS employee repaying refunded CSRS service. OPM runs both the original FERS Act deposit and the newer redeposit and charges whichever is more advantageous to you; this tool computes the one you select.
• Tax. Service credit payments are made with after-tax money and are not deductible.
• Rates that do not exist yet. Payment dates beyond 2026 carry the 2026 rate forward, and the tool labels every posting that relies on that assumption.

Sources

• OPM CSRS/FERS Handbook, Chapter 21 — Service Credit Payments for Civilian Service (PDF) — the deduction percentages (§ 21A2.1-2A), the interest rules (§§ 21A2.1-2B, 21A3.1-2B, 21B2.1-2B) and the crediting effects (§§ 21A2.1-3, 21A3.1-3, 21B2.1-1).
• 5 U.S.C. § 8334(c) and (d) — the CSRS deposit and redeposit, and § 8422(e) — the FERS deposit.
• 5 U.S.C. § 8339(i) — the 10% annuity reduction for an unpaid deposit covering service before 1 October 1982.
• OPM Benefits Administration Letter 11-103 (PDF) — OPM’s implementation of Public Law 111-84 § 1904, the authority for a FERS redeposit.
• OPM Benefits Administration Letter 26-301 (PDF) — the 2026 interest rate of 4.25%.

Last reviewed: August 2026