Vesting in FERS happens at three separate milestones, not one. You need five years of creditable civilian service to be vested in the basic pension, three years to be vested in the agency automatic 1% contribution to your Thrift Savings Plan, and 18 months to qualify for disability retirement or the basic employee death benefit. Your own TSP contributions and the agency’s matching dollars belong to you from the day they hit the account.
Five Years for the Basic Pension
The FERS basic annuity requires at least five years of creditable civilian service before you earn the right to a future pension.1Office of the Law Revision Counsel. 5 USC 8410 – Eligibility for Annuity It’s a hard cutoff. Four years and eleven months earns you nothing from the pension side of FERS. Cross the five-year line and you lock in a guaranteed monthly benefit the government owes you for life, even if you leave federal employment decades before you actually start collecting it.
The retirement deductions withheld from your paycheck are always yours. If you leave before five years, you can request them back. What you forfeit by leaving early is the government-funded portion of the pension, which is the far more valuable piece. That government promise becomes binding only once you hit five years.
Vesting and eligibility to collect are two different things. Being vested means the pension is yours; when you can actually start drawing it depends on your age and total service at separation. A vested employee who leaves mid-career and waits until 62 can begin a full, unreduced annuity at that point.
Three Years for the TSP Automatic 1%
The Thrift Savings Plan runs on its own vesting clock, separate from the pension. Your own contributions and the agency’s matching contributions are fully yours the moment they land in your account. The only piece with a vesting requirement is the Agency Automatic 1% Contribution, which requires three years of civilian service.2Office of the Law Revision Counsel. 5 USC 8432 – Contributions
Two groups face a shorter two-year vesting period for the automatic 1%: certain political appointees, Senior Executive Service noncareer appointees, and individuals in positions excepted from competitive service because of their policy-determining nature.2Office of the Law Revision Counsel. 5 USC 8432 – Contributions Members of the uniformed services also vest in two years.
Leave before meeting the vesting deadline and the automatic 1% contributions plus all earnings on those contributions are forfeited from your account. They don’t come with you; they go back into the TSP’s forfeiture pool. Everything else, including your own contributions, agency matching, and all associated earnings, stays yours regardless of when you leave.
If you later return to federal service, forfeited automatic 1% contributions and earnings can be restored to your TSP account. Your new agency must submit a Form TSP-5-R on your behalf; you can’t file it yourself.3Thrift Savings Plan. TSP Forfeitures and Forfeiture Restoration Procedures Employees who left for military service and return under USERRA are also eligible for restoration.
18 Months for Disability and Death Benefits
FERS has a third, shorter vesting timeline most employees never think about until they need it. Both disability retirement and the basic employee death benefit require only 18 months of creditable civilian service.
Become unable to perform your job due to a medical condition after 18 months of civilian service and you may qualify for a FERS disability annuity.4eCFR. 5 CFR Part 844 – Federal Employees Retirement System, Disability Retirement If an employee dies while still working for the government after at least 18 months, the surviving spouse is entitled to a one-time basic employee death benefit equal to 50% of the employee’s final salary (or average pay, if higher) plus an inflation-adjusted flat amount.5eCFR. 5 CFR Part 843 – Federal Employees Retirement System, Death Benefits and Employee Refunds
A recurring monthly survivor annuity for a spouse has a higher bar. The deceased employee generally needs at least 10 years of creditable service, with at least 18 months of civilian service inside that total.6U.S. Office of Personnel Management. Survivors The surviving spouse must also have been married to the employee for at least nine months, unless the death was accidental or there’s a child of the marriage.
What Counts Toward the Five Years
Not every kind of federal service credits automatically toward vesting. Several types require an extra step before they count at all.
Civilian Service
Standard civilian employment while contributing to the FERS retirement fund is the direct path.7Office of the Law Revision Counsel. 5 USC 8411 – Creditable Service Part-time employees get full credit for the length of their service for vesting purposes. Work part-time for five years and you’re vested. Your eventual annuity amount will be prorated to reflect the actual hours worked, but that’s a benefit-calculation issue, not a vesting issue.
Military Service (with a Buyback)
Prior military service after 1956 can count toward your five years, but only if you make a deposit of 3% of your basic military pay into the retirement fund, plus accrued interest.8U.S. Government Publishing Office. 5 USC 8422 – Deductions From Pay, Contributions for Other Service, Deposits This is the “military buyback.” Skip the deposit and those years won’t count toward vesting or your annuity. Interest keeps building the longer you wait, so paying it early in your civilian career is cheaper.
Peace Corps Service
Peace Corps volunteer and volunteer leader service can be credited toward FERS if you make a deposit based on the stipend you received.9eCFR. 5 CFR Part 842 Subpart K – Peace Corps There’s a two-year interest-free grace period once you become a federal employee. After that window closes, interest starts compounding annually.
Pre-1989 Temporary Service
Certain temporary federal service performed before 1989 can count toward vesting if you pay the required deposit.10eCFR. 5 CFR Part 842 Subpart C – Credit for Service This is a narrow window that mainly matters to longer-tenured employees with early-career temp appointments. Documentation from that era can be spotty, so keep your own records.
Sick Leave Does Not Count
This one trips people up. Unused sick leave gets added to your service time for the annuity calculation, making your monthly payment slightly larger, but it cannot be used to meet the five-year vesting requirement or any other eligibility threshold. Four years and ten months of creditable service plus two months of banked sick leave still leaves you unvested.
Leaving Before You’re Vested
Leave federal service without hitting the five-year mark and you can request a refund of the retirement deductions withheld from your pay.11Office of the Law Revision Counsel. 5 USC 8424 – Lump-Sum Benefits, Designation of Beneficiary, Order of Precedence You must be separated for at least 31 consecutive days, and you file Standard Form 3106 with OPM.12Office of Personnel Management. Application for Refund of Retirement Deductions SF 3106 If you have a current or former spouse, their consent is required as well. Taking the refund wipes out all rights to a future annuity based on that period of service.
The refund includes your actual deductions plus interest if your covered service totaled more than one year. The portion representing your original deductions (contributed with after-tax dollars) comes back tax-free. Any interest included in the refund is taxable, and if OPM pays that interest directly to you rather than rolling it into a qualified plan, they withhold 20% for federal taxes.13Office of Personnel Management. FERS Refund Fact Sheet Rolling the interest portion into a traditional IRA or another qualified plan defers the tax.
Leaving After You’re Vested
Cross the five-year line and leave before retirement age and you have a choice: take a refund now or leave your contributions in the system and collect a deferred annuity later. Most people underestimate how much the deferred annuity is worth.
A vested former employee with five or more years of civilian service can begin collecting a full, unreduced annuity at age 62 by filing Form RI 92-19 with OPM roughly 60 days before the desired start date.14Office of Personnel Management. Application for Deferred or Postponed Retirement With 10 or more years of service (including at least 5 civilian years), you can start collecting at your Minimum Retirement Age instead, but a 5%-per-year reduction applies for every year you’re under 62.15U.S. Office of Personnel Management. Eligibility
If you took a refund after an earlier separation and later return to federal service, you can redeposit the refunded amount plus interest to restore credit for that prior service. The redeposit interest rate for 2026 is 4.25%, compounding annually from the date of the original refund. Over a long gap in service, that interest adds up quickly, so run the numbers before deciding whether the repurchased years are worth the cost.