Best Retirement Calculators 2026: 6 Tools Compared

There is no single best retirement calculator. There is a best one for your question. Some answer "will my money last?" in a minute. Some test your withdrawal rule against every market since 1871. Some build a full plan with taxes, accounts and Roth conversions, and charge for it.

We compared six popular tools from their own websites in October 2026. A disclosure first: we build one of them, Retirement Lab. We have tried to be fair, say where the others are better, and quote only what each tool's own site states. Prices change, so check before you pay.

Quick picks

• Will my money last, quickly and without signing up: Retirement Lab (free).
• A full plan with US taxes and Roth conversions: ProjectionLab or Boldin (paid tiers).
• Test a withdrawal rule against market history: FI Calc or cFIREsim (free).
• The classic historical check: FIRECalc.

The six tools side by side

As listed on each tool's site, October 16, 2026.

Monte Carlo or history?

The tools split into two camps. Historical calculators (FI Calc, cFIREsim, FIRECalc) run your plan through every starting year in the record and count how many survived. They show what really happened, but the record holds only so many 30-year periods, and many overlap. Monte Carlo tools (Retirement Lab, ProjectionLab, Boldin) draw thousands of possible futures from return assumptions (how a Monte Carlo retirement calculator works). They can show bad sequences that never happened, but they are only as good as those assumptions. We compare the two in detail in Monte Carlo vs historical backtesting.

If a plan looks good in both, you can trust it more than if it looks good in one.

Retirement Lab

Best for: a fast, honest answer to "will my money last?", without an account.

Strengths. Runs in the browser with no sign-up: age, savings, saving, spending and pension, and you get a success rate in plain language, in today's money, with the chance of running out by each age. The Improve panel shows what saving more, retiring later or spending less does to your odds. Pro ($29 a year or $79 once) adds 50,000 futures, guardrails and other flexible spending rules, fat-tail returns, stress tests such as a crash in your first year, the full historical test against US markets since 1928, and a PDF report.

Limits. Taxes are one effective rate on withdrawals and income: there are no account types, no Roth conversions and no state tax rules. It does not link to your accounts or track net worth. If your main question is tax planning, the paid planners below fit better.

ProjectionLab

Best for: people who want a detailed, long-range plan and enjoy building it.

Strengths. The free Basic tier already includes Monte Carlo simulations and historical backtesting. Premium ($129 a year) lists cash-flow projections, tax estimation, Roth conversions, ACA subsidies, capital gains harvesting, estate planning, international planning, compare mode and downloadable reports. Monte Carlo can use custom probability distributions.

Limits. The depth takes time to set up. The tax and planning features that set it apart are in the paid tier.

Boldin

Best for: a full US retirement plan with taxes, Social Security and Roth conversions, and the option of a human advisor.

Strengths. PlannerPlus ($168 a year after a 14-day trial) lists state and federal tax projections, a Roth conversion explorer, a Social Security explorer, side-by-side scenarios, account linking and Monte Carlo analysis. Boldin also sells a one-off retirement plan checkup with a Boldin advisor (listed at a $3,200 flat fee).

Limits. Monte Carlo is not in the free Basic plan. Its pricing page describes US accounts and taxes (IRAs, 401(k)s, federal and state tax).

FI Calc

Best for: comparing withdrawal strategies against history, for free.

Strengths. Free, with no paid features (donations unlock nothing). It backtests 13 withdrawal strategies, from constant dollar and percentage of portfolio to VPW, Guyton-Klinger, the 95% rule and Vanguard's dynamic spending, and shows how volatile your spending would have been, not just whether the money lasted. Results export to CSV.

Limits. Historical only, with no tax settings listed. It is a withdrawal-strategy lab, not a full plan.

cFIREsim

Best for: detailed historical testing, including gold and glide paths.

Strengths. Runs your plan through every period since 1871, with stocks, bonds, gold and cash, glide paths, Social Security for two people and pensions. Spending rules include inflation-adjusted, percentage of portfolio with floor and ceiling, variable spending, Hebeler's autopilot, VPW and CAPE-based withdrawals. It can solve for the maximum spending that always survived.

Limits. It does not distinguish between taxed accounts, and its data and inflation are US-based.

FIRECalc

Best for: the classic, quick historical sanity check.

Strengths. Online since 2000, according to its copyright notice. It shows every starting point since 1871 and can solve for the spending or portfolio needed for a target success rate. FIRECalc says it does not store what you enter.

Limits. It ignores taxable versus non-taxable accounts, and offers fewer spending rules than FI Calc or cFIREsim.

Use two, not one

The tools answer different questions, so combining them is cheap insurance:

1. Get the answer. Run your plan in a Monte Carlo tool and see the chance it lasts, and when it fails, how late.
2. Check it against history. Put the same savings and spending into FI Calc or cFIREsim. If history and the simulations broadly agree, good.
3. Plan the taxes. If you have several account types or are weighing Roth conversions, that is where a paid planner earns its price.

Whatever you use, the inputs matter more than the tool. A realistic spending figure and an honest pension estimate move the answer more than any feature. For the question most people start with, see how much do I need to retire? and when can I retire?