What to use instead of FIRECalc

The product

FIRECalc is a free retirement calculator that has been online since 2000, judging by its own copyright line, and is now at version 3.0. You enter what you spend, what you have and how many years the money must last. It then replays that plan against every starting year in its US data, from 1871 onward, and reports how many of those historical cycles ended with money left. A 30-year plan entered with the default inputs on 9 October 2026 ran 126 cycles. The idea comes from the Trinity study and John Greaney's Retire Early spreadsheet, and the site's FAQ credits both.

Underneath the home page there is more than most people find, all of it read on 9 October 2026:

• Spending models: constant inflation-adjusted spending, Ty Bernicke's "Reality Retirement Plan", which cuts real spending by 2 to 3 per cent a year from age 56 to 76, and a percentage of the remaining portfolio with an optional floor that approximates the 95% Rule.
• Inflation on CPI, PPI or a fixed rate you type in.
• Income and outflows: two Social Security amounts with start years, three pension or "off-chart" lines with an inflation switch, and three one-off lump sums.
• Portfolio: a stock and fixed-income split since 1871, with commercial paper, the long interest rate, 30-year or 5-year Treasuries as the fixed-income series. Alternatively, eight asset classes since 1927, a constant growth rate, or a random-performance mode with a mean and a standard deviation. Rebalancing is annual, at each withdrawal.
• Investigate: sweeps over allocation, fees and retirement date, a solver for the spending or starting portfolio that hits a target success rate, and a spreadsheet of the data and formulas for one cycle, for 30-year terms only.

The data is maintained; the software mostly is not. The home page says the data was updated on 17 April 2026 with data through 1 January 2026, and the change notes show a data refresh almost every spring since 2013. The last change to the calculator itself in those notes is a fix dated 5 January 2018, and version 3 dates from November 2007. Nothing has happened to FIRECalc. What happens is that people outgrow it: they want taxes, account types or a spending rule it does not offer, or a non-US history.

Support is a forum, not an inbox. The contact page sends "why does it" questions to the FIRECalc section of the Early Retirement forum. That forum put a browser challenge in front of us on 9 October 2026, so nothing on this page is quoted from it. A "supporters" login, granted on the honour system to anyone who has donated, unlocks "an extra feature or two", such as yearly spending revisions. The site stores nothing you type, according to its privacy page, and it carries ads.

What to use instead

Decide which question FIRECalc was answering for you. It is usually one of four.

"Would this spending plan have survived every past market?" This is FIRECalc's own job, and two free tools do it with more controls. FI Calc replays every US cycle since 1871 with twelve withdrawal strategies, among them Guyton-Klinger guardrails, VPW, a CAPE-based rule and Vanguard Dynamic Spending, each with its own parameters. cFIREsim runs the same method with eight spending plans, two Social Security streams, pensions, up to eighty income and expense adjustments and a gold sleeve. Both are browser-only and need no account. Both are also quieter than they look: cFIREsim's changelog ends in September 2022 and FI Calc had not added 2025 data when its card was written, so neither is a move to a busier project.

"What does my actual plan look like, with taxes?" FIRECalc has one pot of money and no tax. ProjectionLab models accounts, federal and state tax, RMDs, Roth conversions and Social Security from your primary insurance amount. Its free plan runs Monte Carlo and sequential historical backtesting; tax estimation is Premium, at 129 dollars a year. Boldin goes deepest on US retirement rules, including Medicare and IRMAA. Its chance of success is a Monte Carlo drawn from a normal distribution rather than replayed history, and that part sits on PlannerPlus at 144 dollars a year. The ProjectionLab against Boldin page splits that pair.

"What allocation, and from which country?" FIRECalc's histories are US-only. Portfolio Charts draws how any asset mix behaved after inflation from 1970, in twelve home countries' own currencies, and its Withdrawal Rates chart is the historical answer for a non-US retiree, without the plan inputs. testfolio takes your own tickers on daily data and has a withdrawal calculator and cashflow schedules. Its US series reach back to 1885, partly through simulated pre-inception segments that the vendor labels as such.

"What if the future is not a replay?" FIRECalc's random-performance mode is one mean and one standard deviation. testfolio's free Monte Carlo is capped at 15 years and 500 runs; ProjectionLab resamples history as a block bootstrap as well as sequentially. Read why retirement calculators disagree before you compare two of these numbers, and the Monte Carlo glossary entry for what the method assumes.

What you give up

The spreadsheet with the formulas. FIRECalc's Investigate tab will produce a spreadsheet for one cycle with the formulas in it, so you can check every year's arithmetic yourself. FI Calc and cFIREsim export CSVs of values — cFIREsim's runs to 24 columns a year for every cycle — but a CSV shows you what was computed, not how. If auditing the calculation was the point, that is a real loss.

The forum built around it. FIRECalc's FAQ says many of its features were suggested and tested by members of the Early Retirement Forum, and its contact page routes questions there. Results quoted in that archive are FIRECalc results. Move to FI Calc or cFIREsim and your numbers stop lining up with it, even on the same plan, because the calculators pick different bond series, inflation series, fee defaults and cycle counts.

The 1927 asset-class mix. FIRECalc's mixed portfolio splits equities into micro cap, small, small value, large value and the S&P 500, beside long-term Treasuries, corporate bonds and one-month bills. FI Calc and cFIREsim offer stocks, bonds, cash and, in cFIREsim, gold. To get a small-value tilt into a historical withdrawal test you need Portfolio Charts or testfolio, and neither models Social Security or a pension.

Nothing on price. FIRECalc is free, and so are FI Calc, cFIREsim, Portfolio Charts and the free plans of ProjectionLab, testfolio and Boldin. Money only changes hands when you want a tax engine.

Migration notes

Save the scenario first. FIRECalc's results page carries a "Link to this set of data" that reloads your inputs. Bookmark it before you start retyping, because the site keeps nothing on its side.

Expect a different success rate for the same plan. FIRECalc defaults to the long interest rate for bonds, a 0.18 per cent fee and annual rebalancing at the withdrawal date. FI Calc uses the 10-year Treasury yield and a fixed cash rate of 1.5 per cent by default, and cFIREsim a 0.25 per cent cash rate. Cycle counts differ by a year or two at each end of the data. Match the series, the fee and the term before you conclude that one tool is more pessimistic than the other.

Re-enter Social Security in the new tool's terms. FIRECalc takes an annual amount in today's dollars and a start year. cFIREsim takes two streams in the same spirit. FI Calc treats Social Security as a generic income stream. ProjectionLab computes it from a primary insurance amount, with early-claiming reductions, delayed credits and spousal benefits, and Boldin builds a claiming-age explorer around it. Those two are not asking for the same number FIRECalc did.

Taxes move from your head into the model. In FIRECalc, FI Calc and cFIREsim you gross up spending by your expected tax bill. In ProjectionLab Premium and Boldin PlannerPlus you enter net spending and the engine adds the tax. Carrying a grossed-up figure into those tools counts the tax twice.