About PensionMath
Retirement calculators built on IRS rules and each plan's published formulas, checked against the official sources. Your plan's own documents always control.
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 rules private plans have to follow, and public systems publish their benefit formulas in member handbooks. That math shouldn't be buried in a PDF nobody reads.
The core calculator uses the IRS Section 417(e)(3) minimum present value method, which sets the smallest lump sum a private-sector plan may pay. State and local systems aren't bound by 417(e), and most don't offer a lump sum at all. We also cover federal retirement (FERS and CSRS), military retirement, Social Security scenarios, workplace savings accounts, and state pension systems across all 50 states.
Every calculator runs free with no account. A one-time $19.99 purchase unlocks full results on some pages and the PDF and PNG reports.
What the site covers
Pension lump sum
IRS 417(e)(3) present value using the three segment rates: the minimum lump sum a private-sector plan must pay if it offers one.
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age, the earnings test for people who claim before full retirement age, and historical WEP/GPO calculators (both repealed by the Social Security Fairness Act).
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 2023 after rates rose through 2022.
2026 Segment Rates (November 2025 lookback)
Segment 1
First 5 years of payments
4.07%
Segment 2
Years 6 through 20
5.15%
Segment 3
Year 21 and beyond
6.01%
The applicable mortality table is the IRS table for 2026 distributions (Notice 2025-40). The calculator uses the November 2025 segment rates, which many calendar-year plans apply for 2026, and we update the default each year when the November rates publish; enter your plan's own month under custom rates. If you're evaluating a buyout offer, the rates that apply depend on your plan's lookback month and stability period, which your plan documents state.
How the site is paid for
Every calculator runs free with no account. The site is paid for by the optional $19.99 report and by ads shown to visitors who haven't purchased. Ads never appear inside calculation results. We keep basic usage analytics (pages viewed, calculators run) and the email you give at checkout or for rate alerts, and we don't sell any of it. See the privacy policy for details.
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.
Ready to run the numbers?
The IRS 417(e) calculator takes about 60 seconds and shows you the math behind your lump sum offer.