Retirement Lab uses Monte Carlo and historical-cycle simulation, a fat-tail-aware return distribution, and bracket-based tax modeling across 26 supported countries. The comparison below maps where it lines up with other widely-used retirement calculators and where it differs.
Try Retirement LabThe table below summarizes how Retirement Lab, FIRECalc, FICalc, Projection Lab, and Boldin handle the same modeling decisions. Source links in each column header point to that calculator’s own documentation so the underlying claims can be re-verified.
| Feature | Retirement Lab | FIRECalc | FICalc | Projection Lab | Boldin |
|---|---|---|---|---|---|
| Simulation method | Monte Carlo (10,000 paths) and historical-cycle replay | Historical-cycle | Historical-cycle | Monte Carlo (up to 2,000 paths) and historical/bootstrap | Monte Carlo (1,000 paths) and deterministic |
| Return-distribution model | Log-normal with a fat-tail skewness adjustment, or historical-cycle replay | Replays historical equity/bond series | Replays historical equity/bond series | Historical bootstrap or parametric inputs | Historical-based with user override sliders |
| Tax modeling | Bracket-based income, capital gains, and (where applicable) wealth tax | No tax module (include taxes in spending) | No formal tax module (gross of tax) | Tax Estimation in Premium tier | U.S. federal plus state brackets |
| Country support | 26 supported countries | U.S. only | U.S. only | U.S. with International Planning in Premium tier | U.S.-focused |
| Withdrawal-strategy options | Fixed, VPW, Guyton-Klinger, guardrails, CAPE-based, endowment, 95% rule, Vanguard dynamic, lean-times, dynamic SWR | Constant, percentage-of-portfolio, guardrail variants | CAPE-based, VPW, percentage-of-portfolio, constant, and others | Custom cash-flow rules engine | Custom cash-flow rules engine |
| Free vs paid | Free; 30-day Pass ($30 once) or Pro subscription ($10/month or $80/year) for planning extras | Free | Free | Free tier with feature limits; paid subscription | Free tier with feature limits; paid subscription |
| Account required | No | No | No | Yes (to save scenarios) | Yes (to save scenarios) |
Last reviewed: 2026-05. Sources: firecalc.com, ficalc.app, projectionlab.com, boldin.com.
Retirement Lab’s distinguishing feature is streamlined what-if comparisons: scenarios, portfolios, savings rates, residency country, and U.S. state are first-class inputs you can swap and re-run side by side without rebuilding a plan. The simulator pairs that with bracket-based income, capital-gains, and (where applicable) wealth-tax modeling across 26 supported countries, plus 10,000-path Monte Carlo with a fat-tail-aware return distribution. Anonymous users get the full simulation with no account; signing up adds saved, shareable scenarios; the Pro tier opens up planning-depth tools. Try Retirement Lab.
FIRECalc’s distinguishing feature is historical-cycle simulation: it replays every overlapping multi-year period in U.S. market history rather than synthesizing returns from a probability distribution. Many users find that framing intuitive because every modeled sequence is a real historical period. FIRECalc has no formal tax module — taxes are handled by including them in the annual spending input — and country support is U.S.-only. Retirement Lab uses Monte Carlo draws with a fat-tail-aware return distribution instead, which is a different statistical assumption about how future returns might be shaped. Visit firecalc.com.
FICalc’s distinguishing feature is its open catalog of withdrawal strategies — CAPE-based, VPW, percentage-of-portfolio, constant, and others — each tunable, all powered by historical-cycle simulation. The interface is browser-only and free with no account. There is no formal income or capital-gains tax module, so simulated portfolio values are gross of tax. Retirement Lab pairs a similar catalog of strategies with bracket-based tax modeling across 26 supported countries. Visit ficalc.app.
Projection Lab’s distinguishing feature is its detailed cash-flow rules engine, which lets users layer income events, tax-deferred contributions, and complex retirement-account ordering rules with year-by-year granularity. It supports both Monte Carlo (up to 2,000 paths) and historical-bootstrap methods. The Premium tier advertises Tax Estimation, Roth conversions, ACA subsidies, and International Planning, while the free Basic tier is feature-limited and saving scenarios requires a registered account. Where the two diverge: Retirement Lab keeps tax modeling, 26-country coverage, and account-free use on the free tier, and uses fat-tail-aware Monte Carlo rather than historical bootstrap by default; Projection Lab leans on its cash-flow rules engine for U.S.-centric planning and surfaces tax and international modeling at the Premium tier. Visit projectionlab.com.
Boldin (formerly NewRetirement) bundles retirement projections with planner-style modules for U.S.-specific decisions like Social Security claiming, Roth conversion timing, and Medicare. The simulation supports both Monte Carlo (1,000 paths) and deterministic projections with U.S. federal and state tax modeling. A free tier exists; the PlannerPlus tools require a paid subscription and a registered account. International tax modeling is not the focus. Visit boldin.com.
Related reading on the modeling choices behind these comparisons: FIRE calculator on the home page, Monte Carlo retirement simulator, and the methodology page.
There is no single answer — different calculators emphasize different modeling choices. Retirement Lab focuses on Monte Carlo simulation paired with bracket-based tax modeling across 26 supported countries. FIRECalc and FICalc focus on historical-cycle replay using past market sequences. Projection Lab and Boldin focus on detailed cash-flow rules engines for U.S. retirement-account ordering. The right fit depends on which assumptions and country coverage match your situation.
Monte Carlo simulation draws each year’s return from a probability distribution calibrated to historical statistics — mean, volatility, and (optionally) fat-tail skew. Each of the 10,000 paths is a synthetic but statistically plausible future. Historical-cycle simulation replays the actual yearly returns from past market history, starting at every possible offset year. Each modeled sequence is a real period; the universe of futures is bounded by what already happened. Both approaches are valid. Monte Carlo can sample drawdowns deeper than any single historical sequence; historical-cycle never invents an outcome that has not been seen. More on the Monte Carlo approach and on the assumptions Retirement Lab uses.
Retirement Lab, FIRECalc, and FICalc are free. Retirement Lab and FIRECalc require no account; FICalc is browser-only. Projection Lab and Boldin offer free tiers with feature limits and require a paid subscription plus a registered account for the full planner. Pricing changes over time, so verify on each tool’s pricing page before committing.
None of these calculators offer one-click portability between each other today. Account balances, scenario inputs, and assumption settings need to be re-entered when switching. If you are evaluating Retirement Lab against a tool you already use, the practical workflow is to copy the same balances, ages, and country into a new scenario manually. For comparing simulated paths side by side, the FIRE calculator on the home page and methodology page document Retirement Lab’s underlying assumptions.