Model US Social Security and UK State Pension Together — Free
See both pensions as one number, in the currency you actually spend.
You've probably already found a calculator or two. Here's what this one does differently: enter your US Social Security estimate and your UK State Pension forecast as two separate entries, and RetireFlexi combines them — converted to your reporting currency — into a single guaranteed income floor, stress-tested against 5,000 market scenarios for whatever you're drawing from investments on top.
US Social SecurityUK State Pension401(k) / IRASIPP / ISAMulti-currencyMonte Carlo
Add US Social Security and UK State Pension as two separate entries. RetireFlexi combines them into a single guaranteed income floor.
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Real currency conversion
Live exchange rates convert GBP and USD into whichever currency you actually spend. Update your accounts once; the conversion runs every time you open the calculator.
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5,000-scenario stress test
Monte Carlo simulation shows the real probability your combined income and portfolio hold up — not a single best-guess line on a chart.
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Nothing to sign up for
No account, no email required to see your numbers. Your financial data never leaves your browser.
The January 2025 Change Most Calculators Haven't Caught Up To
For decades, drawing a UK State Pension could quietly reduce your US Social Security under a rule called the Windfall Elimination Provision. A lot of advice — and a lot of older calculators — still assumes it applies.
It doesn't, anymore. The Social Security Fairness Act repealed WEP and the Government Pension Offset in January 2025. Enter your full SSA figure with no manual haircut — RetireFlexi reflects the current rules. The complete calculator guide walks through every field, plus a worked example.
Free, With No Trial Clock Running
No credit card at signup, because there's no signup. No 14-day trial that quietly becomes a subscription. No results locked behind a paywall after you've already entered your numbers. RetireFlexi is free because it started as a personal project — the founder needed exactly this and built it for himself first.
No Account, No Data on a Server
Everything you enter — account balances, pension estimates, income targets — stays in your browser on your device. There's no RetireFlexi database of retirement plans, so there's nothing to breach. If you save a plan, it's emailed to your own inbox as an attachment; RetireFlexi never reads or stores what's in it.
No login wall before you can see your results
No server-side storage of any financial figures you enter
Save via email is optional, and the contents are never read by RetireFlexi
Common questions before you start
Can I actually claim both US Social Security and the UK State Pension?
Yes. They're entirely independent systems — qualifying for one has no effect on the other. If you paid into both during your working life, you can receive both simultaneously in retirement. Full mechanics here, including how the Totalization Agreement works.
Does this calculator already reflect the WEP repeal?
Yes. Enter your full US Social Security estimate exactly as shown on your SSA statement — no manual reduction needed. The Windfall Elimination Provision was repealed in January 2025.
Does it convert between GBP and USD automatically?
Yes, using live exchange rates fetched when you open the calculator, converted into whichever reporting currency you choose.
Is my financial information private?
Completely. Everything you enter stays in your browser on your device — see the privacy section above for exactly how that works.
Is it actually free, or is there a paid tier?
Free, with no paid tier at all and no account required to use it.
Model Your Combined Income in About Five Minutes
Enter both pensions, set your draw ages, and see the year-by-year picture — free, and nothing you enter leaves your device.
Not financial advice. This calculator is a planning tool, not personalized tax or pension advice. Pension rules, tax treaties, and benefit amounts change — verify your own entitlement at ssa.gov and gov.uk, and consult a qualified adviser familiar with both US and UK retirement law before making decisions.