Your Retirement Service Computation Date is the clock the government uses to measure creditable federal service, and that number is plugged straight into the formula that sets your federal annuity. Get the date right and every year you worked shows up in your monthly check. Get it wrong — or leave a deposit unpaid — and the pension shrinks for life. Under FERS, a single missing year costs roughly 1 percent of your high-3 salary, every month, forever.
How the SCD Drives the Annuity Formula
The retirement SCD supplies the years-of-service figure in the pension calculation. Under FERS, the basic annuity is 1 percent of your high-3 average salary multiplied by your years of creditable service. Retire at 62 or later with at least 20 years in, and the multiplier rises to 1.1 percent.1U.S. Office of Personnel Management. Computation Your high-3 is the highest average basic pay across any three consecutive years, usually the last three.
CSRS is more generous: 1.5 percent of the high-3 for the first five years of service, 1.75 percent for years five through ten, and 2 percent for every year after that.2Office of the Law Revision Counsel. 5 USC 8339 – Computation of Annuities Either way, the years number in the formula is whatever your SCD produces. That is why the mechanics below matter: each one either adds to that number or leaves a hole in it.
Civilian Service That Counts Automatically, and Service That Doesn’t
Most federal civilian employment feeds the SCD without any action on your part. Permanent, career-conditional, and term appointments where retirement deductions were withheld from your pay all accumulate automatically, along with certain international-organization service and some nonappropriated-fund positions if you elect to have them credited.3Office of the Law Revision Counsel. 5 USC 8411 – Creditable Service
Temporary appointments and other non-covered periods are different. The work happened, but the government took no retirement contributions from your pay, so the time sits outside your SCD as a gap. Service performed before 1989 without deductions can be made creditable under FERS by paying a deposit equal to what would have been withheld, plus interest.4U.S. Office of Personnel Management. Service Credit The interest rate for 2026 is 4.25 percent, compounded annually.5U.S. Office of Personnel Management. Benefits Administration Letter 26-301 Waiting makes it worse. The deposit has to be completed before your annuity begins.
Part-Time Service
Part-time service counts on a full calendar-time basis for retirement eligibility, so three years part-time counts as three years toward the minimum needed to retire.6U.S. Office of Personnel Management. CSRS FERS Handbook – Chapter 55 The annuity itself, though, is prorated by actual hours worked versus full-time hours available. Ten years at 20 hours a week counts as ten years of eligibility but roughly half a decade of pension.
Military Service and the Buy-Back
Active-duty military time can be added to your SCD through the military deposit, commonly called the buy-back. For FERS employees, the deposit is 3 percent of the military basic pay you earned in uniform, with two narrow exceptions: 3.25 percent for 1999 service and 3.4 percent for service in 2000.7Office of the Law Revision Counsel. 5 USC 8422 – Deductions From Pay and Contributions for Other Service Under CSRS, the deposit is 7 percent of military basic pay.8U.S. Office of Personnel Management. Military Deposits
For post-1956 military service under FERS, the deposit is not optional. The statute credits that time only if the deposit is paid.3Office of the Law Revision Counsel. 5 USC 8411 – Creditable Service Pre-1957 military service is credited automatically.
The Interest-Free Window
Both systems give a grace period on the military deposit. The interest accrual date falls three years after you first enter or return to a position covered by civilian retirement deductions.8U.S. Office of Personnel Management. Military Deposits Pay the full amount inside that window and you owe nothing beyond the base. After it, interest compounds annually at the variable rate, 4.25 percent for 2026.5U.S. Office of Personnel Management. Benefits Administration Letter 26-301 Wait 15 or 20 years and the balance can double.
Catch-62 for CSRS-Component Employees
Employees with a CSRS component in their retirement (generally those first hired before October 1, 1982, and FERS transferees carrying CSRS service) face a second penalty for skipping the deposit. If you don’t pay it and you become eligible for Social Security at 62, your annuity is recomputed and all credit for post-1956 military service is stripped from the CSRS portion.4U.S. Office of Personnel Management. Service Credit The pension drops at 62 even though the military years were counted in every check before then. The reduction is permanent.
Pay Before You Separate
The military deposit has to be paid in full before you separate from federal service. You cannot start or finish the buy-back after retirement.4U.S. Office of Personnel Management. Service Credit Retire on a Friday with an unpaid balance, and the military time is gone from your annuity calculation for good.
Leave Without Pay
Extended LWOP can push your SCD back. Under both FERS and CSRS, up to six months of non-pay status in a calendar year is creditable; anything beyond six months in the same calendar year is not, and your SCD moves back by the excess.9Office of the Law Revision Counsel. 5 USC 8411 – Creditable Service
Two situations get full credit regardless of length: LWOP while performing military service, and LWOP while receiving federal workers’ compensation benefits.10Office of the Law Revision Counsel. 5 USC 8332 – Creditable Service If you took extended LWOP for anything else, look at how your SCD was adjusted.
Refunded Contributions and Redeposits
If you left federal service at some point and cashed out your retirement contributions, that earlier service still counts toward eligibility to retire. It does not count toward the annuity computation unless you pay a redeposit of the refunded amount plus interest.11U.S. Office of Personnel Management. Former Employees Eligibility gets you to the door; the computation is what determines the check. Skip the redeposit and those earlier years contribute nothing to your monthly payment.
Redeposit interest runs at the same variable rate as other service credit accounts, 4.25 percent for 2026.5U.S. Office of Personnel Management. Benefits Administration Letter 26-301 A $5,000 refund taken 20 years ago can cost substantially more today. Redeposits, like other deposits, should be completed before your annuity starts.
Unused Sick Leave
Sick leave does not change your SCD, but it does add time to the annuity computation. For any FERS employee retiring after December 31, 2013, 100 percent of unused sick leave hours are converted into extra service time for the pension calculation.12Office of the Law Revision Counsel. 5 USC 8415 – Computation of Basic Annuity CSRS employees get the same full credit. The conversion uses the 2,087-hour work year.
Two limits. Sick leave credit cannot be used to meet the minimum service requirement to retire, and it does not enter the high-3 salary calculation. It layers onto your service total at the end. An employee at 29 years and 6 months of creditable service with about 1,044 banked sick leave hours can reach 30 years for computation purposes, which adds real money to every month’s check.
Verifying Your SCD
The core document is the SF-50 (Notification of Personnel Action). Every appointment, promotion, reassignment, and separation generates one, and each records the effective date and type of action. The full set lives in your electronic Official Personnel Folder (eOPF) and, taken together, forms the timeline behind your SCD.13U.S. Office of Personnel Management. Standard Form 3108 – Application to Make Service Credit Payment
Documenting a service credit claim uses different forms depending on your system. CSRS employees file SF-2803 (Application to Make Deposit or Redeposit). FERS employees file SF-3108 (Application to Make Service Credit Payment).13U.S. Office of Personnel Management. Standard Form 3108 – Application to Make Service Credit Payment Both require exact dates and earnings for each period of non-deduction service. For a military buy-back, you’ll also need your DD-214 to confirm dates, branch, and character of discharge.
Don’t wait until the year you plan to retire to look at any of this. Missing SF-50s, unexplained gaps, and an SCD that doesn’t match your actual start date can take months to resolve. Compare your eOPF against your LES periodically so problems surface while there’s still time to fix them.
Filing a Service Credit Application
Current employees submit the completed application, supporting documents, and any DD-214s to their agency’s HR or benefits office, which verifies and forwards the case. Former federal employees no longer on the rolls send applications directly to OPM’s Retirement Operations Center.
You’ll receive a billing statement showing the deposit or redeposit amount and any accrued interest. Partial payments are allowed, but the balance must be paid in full before the annuity starts if the service is going to count in the computation. Interest keeps running on any unpaid portion until either the deposit is complete or the annuity commences.4U.S. Office of Personnel Management. Service Credit
Once payment is processed, you’ll receive confirmation with an updated service history, and the revised SCD should appear on your LES within a couple of pay periods. If it doesn’t, follow up with HR. Corrections that stall at this stage are common enough that a check-in is worth the time.