Your Service Computation Date Is Not Your Hire Date

Almost every date in a federal retirement — the earliest day you can go, the day 30 years is reached, the day an early-retirement window opens — is counted forward from a single date called the service computation date. It is not the day you were hired. It is a date your agency built by taking your hire date and moving it backwards by the earlier service you are allowed to count, so that the arithmetic afterwards is simple: 30 years of service is the 30th anniversary of that date.

Two things go wrong with it, and they go wrong in opposite directions. People read the wrong SCD off their own paperwork and think they are further along than they are. And people assume that service they performed appears in it automatically, when for several kinds of service it does not appear unless they pay for it.

There are two SCDs, and the one you see is usually the wrong one

The date printed on your leave and earnings statement is a leave SCD. It exists to set your annual leave accrual rate, and it is computed under a different statute — 5 U.S.C. § 6303 — which counts kinds of service that retirement law does not. The most common divergence is military service: it can raise your leave accrual without being creditable toward your annuity, because those two questions are answered by two different laws.

The retirement SCD is the one in block 31 of your SF-50, labelled Service Comp. Date. That is the date the eligibility rules are dated from. If your leave SCD is three years earlier than your retirement SCD, you accrue leave as though you have three more years than you can retire on, and both records are correct.

Check the retirement SCD before you plan anything around it. It is constructed by a human being from your service history, it is the input every other date depends on, and an agency that has never been asked to verify it has never had a reason to look at it twice.

What is missing from an SCD, and why

Four kinds of federal service commonly fail to appear in a retirement SCD. In each case the reason is a rule, not an oversight.

Temporary or seasonal service with no retirement deductions. Under FERS, non-deduction service performed on or after 1 January 1989 is not creditable at all, and no payment can make it creditable — 5 U.S.C. § 8411(b)(3) is a bar, not a price. Non-deduction service before that date is creditable if a deposit is paid. This is the rule that most often surprises someone who spent two or three years as a temp before converting: those years are gone, and they were gone the day they were worked.

Service you took a refund for. If you left federal service and withdrew your retirement contributions, that time comes back only if you repay it with interest. Under FERS the repayment was not even legally possible until Pub. L. 111-84 § 1904 authorised it on 28 October 2009. Under CSRS the answer splits on a date: refunded service that ended before 1 October 1990 is credited whether or not you repay it, with the annuity actuarially reduced instead, while later refunded service is not credited until the redeposit is made.

Military service. Post-1956 active duty is creditable toward a FERS annuity only if you make a deposit of 3% of your military basic pay. A two-year grace period runs from the date you are first employed in a covered position, and because interest is only ever assessed on an anniversary of that date, a deposit paid in full before the third anniversary costs principal only. After that it compounds annually — which is why the same purchase costs materially more at 55 than at 30.

Unused sick leave. Sick leave never appears in an SCD, and never counts toward eligibility. It is added to your creditable service at retirement, for the computation only. It cannot make you eligible a day earlier and it cannot carry you over the 20-year line that the 1.1% accrual factor tests.

Two more that are in the SCD but not worth what you would assume

Part-time service counts in full toward eligibility — a part-time year is a year, and your SCD does not care how many hours were in it. The proration happens later, applied to the finished annuity, which is why part-time work never delays a retirement date and always reduces the payment.

A break in service of any length pushes the SCD forward by the length of the break, not by a rounded year. Federal service arithmetic runs on 30-day months and a 360-day year, so a five-week gap between two appointments is a real and specific number of days added to the SCD.

What to do with this

Pull your most recent SF-50 and read block 31. Then pull the SF-50s from any earlier federal appointment and check that the gaps between them are reflected. If you have temporary service before 1989, refunded service, or military service, ask your agency's retirement specialist for the deposit or redeposit balance — and get it in writing, since interest is charged annually and a quote goes stale.

Then take the SCD, not your hire date, into any eligibility calculation. The difference is frequently a year or more, and it moves in whichever direction you have not planned for.

Sources

• 5 U.S.C. § 8411 — FERS creditable service, including the bar at (b)(3) on post-1988 non-deduction service. Text of § 8411
• 5 U.S.C. § 6303 — service creditable for annual leave accrual: the other SCD. Text of § 6303
• OPM CSRS/FERS Handbook, Chapter 21 — Service Credit Payments for Civilian Service. Crediting effects at §§ 21A2.1-3, 21A3.1-3 and 21B2.1-1. Chapter 21 (PDF)
• Pub. L. 111-84 § 1904 — the authority for a FERS redeposit, which did not exist before 28 October 2009. OPM Benefits Administration Letter 11-103 (PDF)

What this guide does not do: it will not tell you whether your own SCD is right. Only your agency can reconstruct that from your service history, and only OPM can settle it at retirement. What it does is name the six things that are commonly missing or misread, so that you know what to ask about.

This guide is informational only. It is not financial, tax, or legal advice, and FedAnnuity is not affiliated with OPM or the U.S. government. Retirement rules turn on the specific facts of a career, and only your agency and OPM can give you a binding figure.

Last reviewed: August 2026 · Against 5 U.S.C. §§ 8411 and 6303, and OPM Handbook Chapters 21 and 23.