Service Computation Date (SCD)
Calculate all four federal service computation dates — Leave SCD, FERS Retirement SCD, TSP SCD, and RIF SCD — in one place. Handles military service, deposit rules, military retiree restrictions, and performance-rating credit.
Reviewed by Jonathan D., 20-year federal employee · Formulas verified against OPM.gov ·
The four service computation dates — what each one governs
Federal employees are assigned up to four different service computation dates, each governing a different benefit system. They can differ from each other by years — and getting one wrong has compounding consequences.
| SCD Type | Authority | What it governs | Military credit rule |
|---|---|---|---|
| Leave SCD | 5 U.S.C. §6303 | Annual leave accrual tier (4 / 6 / 8 hrs/pp) | All active duty (non-retirees) without deposit |
| Retirement SCD | 5 U.S.C. §8412 | FERS eligibility + annuity computation service figure | Deposit paid only (or retired-pay waiver) |
| TSP SCD | 5 CFR §1603 / TSP Bulletin 15-1 | Vesting of Agency Automatic 1% contributions | Civilian service only; floor at 1984-01-01 |
| RIF SCD | 5 CFR §351.503–504 | Retention standing in reductions in force | Leave SCD + performance-rating years |
Leave SCD: the one on every SF-50
Your Leave SCD appears in Block 31 of every SF-50 Notification of Personnel Action. It determines which of three accrual tiers you are in — 4, 6, or 8 hours of annual leave per biweekly pay period. Almost all federal civilian service is creditable here, and for most non-military-retiree employees, active duty military service counts too — no deposit required.
The exception that trips up many employees: if you receive military retired pay, the statute (5 U.S.C. §6303(e)) restricts your Leave SCD credit to service during a declared war, an authorized campaign or expedition, or a disability connected to armed conflict. Waiving your retired pay does not remove this restriction — that is a common misconception verified in OPM guidance. Waiving retired pay helps your Retirement SCD only.
Retirement SCD: the deposit difference
Your FERS Retirement SCD determines when you become eligible to retire and how many service years go into your annuity formula. Civilian service accrues the same way as it does for Leave SCD. Military service, however, requires a paid deposit — 3% of your military basic pay plus interest — before it counts. If the deposit is unpaid, those active-duty years are excluded from your retirement SCD entirely.
Military retirees who have waived their retired pay can credit all military service toward their FERS retirement — unlike Leave SCD, where the waiver has no effect. The waiver must be submitted to DFAS at least 90 days before your planned civilian retirement. See the Military Buyback Calculator to estimate the deposit cost.
TSP SCD: what you lose if you leave too early
Your TSP Service Computation Date governs vesting of the Agency Automatic 1% Contributions — the 1% of salary deposited into your TSP every pay period regardless of whether you contribute. If you leave federal service before vesting, those contributions and their earnings are forfeited. Employee contributions and matching contributions vest immediately.
Most FERS employees need 3 years of service to vest. Noncareer SES employees, Executive Level positions, and Congressional employees vest in 2 years. The TSP-SCD includes all federal civilian service — not just the period while you were enrolled in TSP — but cannot go earlier than January 1, 1984, per TSP regulations (TSP.gov Bulletin 15-1).
RIF SCD: how performance credit shifts your standing
In a reduction in force, agencies rank employees on a “retention register” by competitive level, tenure, veterans' preference, and seniority. Seniority is measured by your RIF SCD — and the earlier your RIF SCD, the higher your standing. The RIF SCD starts with your Leave SCD and then shifts backward by performance-credit years under 5 CFR §351.504.
When multiple ratings of record are used, agencies average the applicable ratings and round any fraction up to the next whole year. This calculator uses a single-rating estimate — if your agency averages multiple recent ratings, the result could differ. A Level 5 rating adds 20 years of seniority credit; Level 4 adds 16; Level 3 adds 12; Level 2 or below adds nothing.
LWOP, part-time, and other nuances
Leave without pay (LWOP) exceeding 6 months of aggregate nonpay status in a single calendar year is not creditable service. The excess days are subtracted from your SCD. This calculator flags LWOP periods but cannot precisely compute the reduction without exact hour records — verify with your HR office.
Part-time employment does not change your SCD date — the SCD is computed using calendar days, not hours worked. Part-time schedules do, however, affect the amount of leave you earn per pay period (prorated by hours in pay status) and can affect your annuity computation under FERS.