About PensionMath
Free retirement calculators built on actual IRS formulas. Not estimates. Not generalizations. The same math plan administrators are legally required to use.
What this site is
PensionMath started from a simple frustration: most pension calculators on the internet either use simplified formulas or make you sign up before showing you anything. The IRS publishes the exact formula plan administrators are required to use. There's no reason it should be behind a paywall or buried in a PDF nobody reads.
The core calculator uses the IRS Section 417(e)(3) minimum present value methodology. That's the same formula your plan administrator runs when they compute your lump sum distribution. We also cover federal retirement (FERS and CSRS), military retirement, Social Security scenarios, workplace savings accounts, and state pension systems across all 50 states.
Everything is free. No account required. That won't change.
What the site covers
Pension lump sum
IRS 417(e)(3) present value using the three segment rates. The formula plan administrators are required to use by law.
Federal retirement
FERS and CSRS pensions, including VERA, MRA+10, and the FERS Supplement for those who retire before 62.
Workplace savings
TSP, 403(b), and 457(b) calculators covering contribution limits, growth projections, and Roth conversion scenarios.
Military retirement
High-3 and Blended Retirement System (BRS) calculations, including TSP matching and SBP decisions.
Social Security
Break-even age, WEP reduction, GPO offset, and the earnings test for those who claim before full retirement age.
State pensions
Benefit formulas for public employee pension systems in all 50 states, plus pension tax treatment by state.
Medicare and RMD
IRMAA thresholds, Part B and D premiums, required minimum distribution tables for IRA and 401(k) accounts.
Employer-specific data
Pension plan details for 29 major employers and unions, including Boeing, AT&T, GM, Ford, Teamsters, and IBEW.
How the lump sum formula works
The IRS Section 417(e)(3) formula splits your expected stream of pension payments into three time buckets and discounts each one at a different interest rate. Those rates are the "segment rates," published monthly by the IRS. A higher rate produces a smaller lump sum. That relationship is why lump sum offers dropped sharply in 2022 and 2023 as rates rose.
2026 Segment Rates (November 2025 lookback)
Segment 1
First 5 years of payments
5.03%
Segment 2
Years 6 through 20
5.35%
Segment 3
Year 21 and beyond
5.57%
The applicable mortality table is RP-2014 projected with Scale MP-2021. We update segment rates each month when the IRS publishes new figures. If you're evaluating a buyout offer, the relevant rates depend on your plan's lookback period, typically the month that's two or three months before your distribution date.
Free calculators, ad-supported
Every calculator on this site is free with no account required. PensionMath is ad-supported: display ads appear in designated slots around the content. They don't appear inside calculation results, and they never will. We don't collect or sell user data.
Important
Results are educational estimates. Tax laws, benefit formulas, and IRS rules change. Before making a pension or retirement decision involving five- or six-figure amounts, consult a fee-only fiduciary financial advisor who can model your specific situation. PensionMath doesn't provide financial, tax, or legal advice. No user data is collected or sold.
Ready to run the numbers?
The IRS 417(e) calculator takes about 60 seconds and shows you the math behind your lump sum offer.