Before you run the estimator, understand the levers. A few decisions — your retirement age, whether you hit 62 with 20 years, how you handle FEHB — can move your lifetime value by hundreds of thousands of dollars.
Your FERS pension formula is simple: High-3 × Years of Service × Multiplier. Every year of creditable federal service adds either 1.0% or 1.1% of your High-3 salary to your annual pension, paid for life and inflation-adjusted.
That doesn't sound like much — until you apply it to a $150,000 High-3 and multiply by 30 years. One additional year of service at $150K adds roughly $1,500/year to your pension, every year for the rest of your life — worth $30,000–$50,000 in present value.
High-3: $152,000 · YOS: 30 · Multiplier: 1.1%
Annual pension: 152,000 × 30 × 0.011 = $50,160/year
One more year (31 YOS): 152,000 × 31 × 0.011 = $51,832/year — an extra $1,672/yr for life.
| Years of Service | Annual pension (High-3 = $150K, 1.0%) | Annual pension (High-3 = $150K, 1.1%) |
|---|---|---|
| 20 years | $30,000/yr | $33,000/yr |
| 25 years | $37,500/yr | $41,250/yr |
| 30 years | $45,000/yr | $49,500/yr |
| 35 years | $52,500/yr | $57,750/yr |
Creditable service includes active federal civilian service, military service you've bought back, and certain leave-without-pay situations. Your Service Computation Date (SCD) — on your SF-50 in box 31 — reflects any adjustments.
Your FERS pension is calculated on your High-3 — the average of the three highest consecutive years of basic pay (including locality) at any point in your career. For most employees, this is simply your final three years, since pay rises over time.
How to find it: Your current base pay (including locality) appears on your SF-50 in block 20, or on your most recent pay stub's "basic pay" line. The estimator projects your High-3 forward based on assumed pay raises and WGI step increases.
Suppose you're promoted from GS-13 ($130K) to GS-14 ($145K) in your final two years.
Your High-3 jumps from roughly $130K to roughly $140K — a $10K increase.
With 30 YOS at the 1.1% multiplier, that's $3,300 more per year in pension, forever —
worth ~$80,000–$100,000 in present value over a typical retirement horizon.
What counts as basic pay: Your GS salary including locality pay. Overtime, bonuses, and awards do NOT count toward High-3.
Part-time service: If you work part-time, your High-3 is prorated to the part-time rate. This is an important edge case not modeled by the estimator.
FERS offers a 10% pension bonus to employees who retire at age 62 or later with 20 or more years of creditable service. The multiplier rises from 1.0% to 1.1%. Both conditions must be met simultaneously at retirement.
High-3: $150,000 · YOS: 28
Age 60 (1.0%): 150,000 × 28 × 0.010 = $42,000/year
Age 62 (1.1%): 150,000 × 30 × 0.011 = $49,500/year
$7,500 more per year for life — just by waiting two years.
Over a 25-year retirement, that's ~$187,500 in nominal terms — and considerably more in present value.
The two-year wait earns you both more YOS (the numerator goes up) and the higher multiplier (the rate goes up). The compounding effect is significant. If you're at 18–19 YOS at 62, it may be worth staying to hit 20.
You must complete 5 years of creditable civilian federal service to vest in your FERS pension. Leaving before the 5-year mark means you receive no FERS pension at all — not a reduced one, not a deferred one. Zero. You get only your own TSP contributions back (plus earnings), but lose the agency match and all pension accrual.
After vesting (5+ years), you are entitled to a deferred annuity at MRA even if you leave federal service. That deferred pension is based on your High-3 salary and YOS at the time you leave — not at retirement age. It doesn't grow with inflation between departure and when you claim it.
4.9 years of service: Leave federal service → $0 in FERS pension, ever.
5.0 years of service: Leave federal service → Deferred annuity payable
at MRA based on your salary and YOS at departure. Could be $8,000–$15,000/year for life
depending on your High-3.
FEHB (Federal Employees Health Benefits) in retirement is one of the most undervalued federal benefits. If you meet the requirements, the government continues paying approximately 70–75% of your health insurance premium for the rest of your life. For a self-plus-family plan, that subsidy is worth $8,000–$15,000 per year — and rises with healthcare inflation.
The requirement: You must have been continuously enrolled in FEHB for the five consecutive years immediately before retirement. A gap in FEHB coverage (e.g., switching to a spouse's plan for a year, or having coverage lapse during a job change) can permanently disqualify you from FEHB in retirement.
How to find your plan's current subsidy value: Check your current FEHB plan's biweekly employee contribution on your leave and earnings statement. Your employer share is typically 70–75% of the total premium — the government pays that portion in retirement too. OPM publishes the full premium table at opm.gov/healthcare-insurance.
FERS employees who retire at MRA (or later) with sufficient service before turning 62 receive an FERS Annuity Supplement — a monthly payment that approximates the Social Security benefit you earned during federal service. It's designed to bridge the gap between your MRA retirement date and age 62 when SS becomes available.
Eligibility:
Amount: Calculated using your federal service years and estimated Social Security earnings. OPM approximates it as: (YOS ÷ 40) × estimated SS benefit at age 62. For a 30-year employee with an estimated $2,000/month SS benefit, the supplement would be roughly $1,500/month ($18,000/year).
The supplement ends at age 62 and is subject to an earnings test: if you earn more than the Social Security annual earnings limit (~$22,320 in 2025 dollars) from post-retirement employment, the supplement is reduced by $1 for every $2 you earn over the limit.
The MRA+10 option lets you retire at your Minimum Retirement Age with as few as 10 years of creditable service. The trade-off: your pension is permanently reduced by 5% for every year you are under age 62 at retirement.
Employee retires at MRA (age 57) with 12 YOS. They are 5 years under 62.
Reduction: 5% × 5 years = 25% permanent reduction.
Base pension: $150,000 × 12 × 1.0% = $18,000/yr
After MRA+10 penalty: $18,000 × (1 − 0.25) = $13,500/yr for life.
One workaround: You can postpone collecting your MRA+10 pension. If you separate at MRA (with 10+ YOS) and delay collecting until age 62, the 5%/year penalty is eliminated entirely. You don't work, but you also don't draw the pension — you wait. This is rarely discussed but can be powerful if you have other income sources to bridge the gap.
MRA by birth year ranges from 55 (born before 1948) to 57 (born 1970 or later). See the MRA table in the Methodology for your exact MRA.
The TSP (Thrift Savings Plan) is a defined-contribution 401(k)-style account. FERS employees receive an automatic 1% agency contribution and up to 4% agency match (total: up to 5% match if you contribute at least 5%). The TSP's power is compound growth.
The leverage of one more percent: An employee earning $100,000 who increases their contribution from 5% to 6% adds $1,000/year in contributions. Over 20 years at 7% growth, that extra $1,000/year compounds to roughly $52,000 additional at retirement — which at a 4% drawdown rate produces ~$2,000/year in additional retirement income.
5% contribution ($5K/yr + 5% match = $10K/yr): balance ≈ $524,000
10% contribution ($10K/yr + 5% match = $15K/yr): balance ≈ $786,000
15% contribution ($15K/yr + 5% match = $20K/yr): balance ≈ $1,048,000
If you're 50 or older: You're eligible for IRS catch-up contributions ($7,500 additional in 2025, on top of the $23,500 regular limit). The full IRS limit for age 50+ is $31,000 in 2025. This is one of the most underutilized benefits for employees in the final decade of their career.
The C Fund context: The TSP C Fund (tracks the S&P 500) has returned approximately 10% annually over 30 years. The L Fund for your target retirement date is a more conservative blended allocation that automatically shifts toward bonds as you approach retirement.
Roth vs. Traditional TSP: The estimator treats TSP as pre-tax (Traditional). If you contribute to Roth TSP, withdrawals are tax-free — your retirement income calculation differs since those funds won't be taxed at withdrawal.
At retirement, you make an irrevocable election about whether to provide a survivor annuity to your spouse. This election cannot be changed after retirement (with very limited exceptions).
The three options:
50% election: Your pension = $45,000/yr (10% reduction).
After your death, spouse receives $25,000/yr for life.
No election: Your pension = $50,000/yr. Spouse receives $0 after your death.
Spousal consent requirement: If you're married and elect no survivor benefit, your spouse must sign a notarized consent form. OPM takes this seriously.
Federal employees' unused sick leave balance at retirement is converted to additional creditable service for the FERS pension calculation. 2,087 hours of sick leave equals one year of service credit.
Employee retires with 1,000 hours of unused sick leave.
Service credit: 1,000 ÷ 2,087 ≈ 0.479 additional years of service.
At a $150,000 High-3 and 1.0% multiplier, that's ~$719/year extra pension, for life.
This is not modeled by the current estimator but can meaningfully improve your pension if you've accumulated significant sick leave over a long career. Employees who rarely use sick leave can accumulate 1,000–2,000 hours or more over a 20–30 year career.
Unlike annual leave, sick leave has no cap and is not paid out at retirement — it converts to service credit. Using sick leave unnecessarily before retirement permanently reduces your eventual pension.
Before running the estimator, gather these five numbers:
Optional: your current GS grade and step let the estimator apply accurate WGI (within-grade-increase) step progressions to your salary projection. Without it, the forecast still works but won't include step increases.
The estimator applies all these factors to your specific career data.
Social Security Coordination
Unlike CSRS employees (hired before 1984), FERS employees contribute to and receive full Social Security benefits. Your federal salary and FERS contributions do not reduce your SS eligibility or benefit amount.
When to claim is a separate decision from when to retire from federal service. You can retire from the government at any eligible age and still claim SS at any point between 62 and 70.
Delaying SS from 62 to 70 can increase your monthly benefit by 32–77% depending on your birth year. For a retiree with a $2,000/month FRA benefit, delaying to 70 means $2,640/month instead of ~$1,400/month — a $14,880/year difference.
Break-even for delaying: If you claim at 62 vs. 70, you start earlier but at a lower amount. The break-even point (when the higher delayed benefit surpasses cumulative early payments) is typically around age 80–82. If you expect to live past 82, delaying is generally advantageous.
How to get your estimate: Create a free account at SSA.gov → to see your projected benefits at different claim ages based on your actual earnings record.