WEP/GPO Calculator — Methodology

How This Calculator Works

This calculator estimates the Social Security benefit changes resulting from the elimination of WEP (Windfall Elimination Provision) and GPO (Government Pension Offset) by the Social Security Fairness Act, signed January 5, 2025. It answers two different questions. If your benefits start in 2024 or later, WEP and GPO never applied to you: the Act covers all benefits payable for months after December 2023, and the calculator shows your ordinary benefit. If your benefits started by December 2023, it shows what WEP and GPO took off each month before January 2024, which is roughly how much your payment rose with the repeal.

Inputs and Assumptions

• Birth year: Determines FRA and early claiming reductions. With your claiming age it gives the year your benefits start (birth year + claiming age), which decides whether WEP and GPO ever applied.
• Years of SS-covered employment: Determines the WEP first bend point factor (scaled 0.40–0.90 based on 20–30 years of substantial earnings).
• Monthly non-covered pension: Your pension from employment not covered by Social Security (teachers, firefighters, some public employees).
• Average annual SS-covered earnings: Used to estimate your Primary Insurance Amount. Each year counts only up to the wage base ($184,500 for 2026) and the result is held to SSA's $4,152 maximum at full retirement age. Figures are in today's dollars (2026 bend points), not the dollars of the year you claimed.
• Spouse's PIA: For GPO calculation on spousal/survivor benefits.

Formula

// Did WEP and GPO ever apply? (Pub. L. 118-273, s. 4)
firstBenefitYear = birthYear + claimAge
applied          = firstBenefitYear <= 2023      // otherwise: no WEP, no GPO

// WEP (benefits before 2024 only)
// Normal first bend point factor: 0.90
// WEP-adjusted factor: 0.40 to 0.90 based on years of SS-covered work
// 30+ years of substantial earnings = no WEP reduction
// 20 or fewer years = maximum WEP reduction (factor = 0.40)
wepReduction = min((0.90 − wepFactor) × min(AIME, firstBendPoint),
                   0.5 × monthlyNonCoveredPension)   // WEP guarantee
wepPIA       = PIA − wepReduction
// Both PIAs are then adjusted for your claiming age:
wepCut       = benefit(PIA, claimAge) − benefit(wepPIA, claimAge)

// Spouse's benefit: only the excess over your own PIA is paid,
// reduced if you claim before full retirement age
// (42 U.S.C. 402(k)(3)(A) and 402(q)(3)(B))
spouseNow    = reduced(max(0, 0.5 × spousePIA − PIA))
spouseBefore = reduced(max(0, 0.5 × spousePIA − wepPIA))

// GPO (benefits before 2024 only), after those reductions
gpoOffset    = (2/3) × monthlyNonCoveredPension
afterGPO     = max(0, spouseBefore − gpoOffset)
gpoCut       = spouseNow − afterGPO

// Increase from the repeal, per month, at your claiming age
increase     = wepCut + gpoCut

Data Sources

• SSA WEP chart — ssa.gov/planners/retire/wep.html — WEP factor table by years of SS-covered employment.
• SSA GPO Publication 05-10007 — Government Pension Offset rules and 2/3 reduction formula.
• Social Security Fairness Act (Pub. L. 118-273, H.R. 82) — Signed January 5, 2025. Section 4: the repeal applies to benefits payable for months after December 2023. Text (govinfo.gov).
• SSA POMS RS 00605.360, RS 00605.362 and RS 00605.369 — WEP, the factor table for benefits payable 1989–2023, and the guarantee; GN 02608.100 — GPO, two-thirds of the pension.
• 20 CFR 404.408a(d)(3); 42 U.S.C. 402(k)(3)(A) and 402(q)(3)(B); POMS RS 00615.020 — the spouse's benefit is reduced for age and for your own benefit before GPO applies.
• Congressional Research Service (CRS) — Report on WEP/GPO impact analysis.

Limitations

• SSA finished its recalculations in July 2025; your actual new benefit is on your SSA record and may differ from this estimate.
• Retroactive payment timing is subject to SSA processing delays.
• Does not model state pension interactions or tax implications of lump sum payment.
• WEP factor estimation requires accurate count of years of "substantial earnings" under SS — the calculator uses a simplified input.
• The year benefits start is taken as birth year + claiming age; someone who turned that age late in the year may have started in the next one.
• The spouse's benefit is assumed to start with your own (applying for one is applying for both) and your spouse to be receiving benefits. Survivor benefits are not modelled.

Last Updated

April 2026 — Reflects Social Security Fairness Act signed January 5, 2025.

October 2026 — SSA finished the recalculations and back payments by July 7, 2025 (SSA, July 10, 2025); the pages now say so instead of describing the work as ongoing.

October 2026 — Anyone whose benefits start in 2024 or later is no longer shown a WEP or GPO reduction. The expected increase is now worked out at the benefit you are paid, not the PIA. GPO now applies only to the spouse's benefit actually payable on top of your own.