FI Calc

FI Calc is a free web calculator for examining retirement plans against a long record of actual market history. It is best suited to people comparing spending, income and portfolio choices who can work without built-in tax or probability modeling. The result is a useful exploratory tool, but not a complete financial-planning system.

Overview

FI Calc replays retirement strategies against annual data from 1871 through 2024, compiled from Robert Shiller’s data set. That historical perspective lets you see how a plan would have behaved through specific past market environments, which is valuable when testing withdrawal rules and allocation changes. It cannot establish what future returns will be, and the maker explicitly says historical results do not guarantee future performance.

James, the creator, says he began the project in 2018. FI Calc is not financial advice; anyone making consequential decisions should consult a licensed financial professional.

Key features

Portfolio and cash-flow scenarios

You can combine equities, bonds and cash, set rebalancing rules, and change allocations over time. The calculator also accepts additional future expenses and income, including wages and Social Security. Income projections, savings-growth projections, withdrawal planning and scenario analysis make it possible to compare a range of retirement paths instead of testing a single fixed withdrawal rate.

Export and analysis

All simulations or an individual simulation can be exported as a CSV file for analysis in the spreadsheet application you choose. That is a practical strength for readers who want to compare runs, retain a record, or add their own calculations outside the calculator.

Important omissions

Taxes and required minimum distributions are not automatically modeled, so the output can overstate spendable income for plans where those items drive cash flow. FI Calc also has no Monte Carlo simulation. Readers who need probability ranges or tax-aware projections will need another tool or their own spreadsheet work.

Privacy and sharing

Inputs are processed in the browser, but saved and shared calculations are encoded in URLs. Those URLs may reach the hosting provider, site services and anyone who receives a link. Google Analytics also receives usage information, including page URLs that may contain saved inputs. Avoid placing sensitive personal figures in shareable calculations unless you accept that exposure.

Pricing

There is no free trial because the product is already free, and no paid tier, seat charge, renewal term or usage quota is stated. The trade-off is capability rather than price: users accept the missing tax and Monte Carlo models and the browser-based sharing and analytics practices.

Platforms

FI Calc runs on the web. No desktop or mobile app platform is provided.

Who it's for

Choose FI Calc if you want to compare historical retirement outcomes while adjusting asset mixes, rebalancing, changing allocations, income and expenses, then move the results into a spreadsheet. It is especially appropriate for self-directed planners who understand that backtesting is illustrative rather than predictive.

Look elsewhere if taxes, required minimum distributions or Monte Carlo probabilities are central to your plan, or if URL-encoded saved inputs and analytics create an unacceptable privacy concern.

Pros and cons

Pros

• Long historical window: annual data from 1871–2024 provides many past market environments for strategy comparisons.
• Flexible scenarios: equities, bonds, cash, rebalancing, allocation changes, wages, Social Security and future expenses can be combined.
• Useful exports: CSV output for all or individual simulations supports deeper spreadsheet analysis.
• No subscription cost: the sole plan costs 0.00 USD and is supported by donations.

Cons

• No tax or RMD automation: after-tax spending plans require manual adjustments.
• No Monte Carlo: it cannot provide probability-based outcome ranges.
• Sharing privacy exposure: saved inputs travel in URLs and page URLs may be collected by Google Analytics.
• Historical limits: past-market results are not forecasts or guarantees.

Alternatives

Boldin is the stronger choice for a broader freemium planning workspace, with Android, iOS and web access, 100-plus inputs, interactive explorers, charts and limited Boldin AI questions on its free Basic plan.

Flexible Retirement Planner fits users seeking a free personal-use calculator across Linux, macOS, Windows and the web.

ProjectionLab is preferable when you want forecasting, flexible modeling, historical backtesting and Monte Carlo simulations, with Android, iOS and web support.

RetireePlan suits readers who want a free-forever, open-source tool available on desktop, web, API and self-hosted setups.

driftcurve is an option for self-hosting and local use without accounts in its default mode.

Fidelity Planning & Guidance Center provides a free web plan without a fee to generate a plan, though investment and transaction costs may still apply.

FIRECalc offers a free core retirement calculator, with supporter registration providing some additional features on request.

Retireator is a free, open-source retirement simulator for the web and Windows.

Browse more options in Retirement Planning Software.

Verdict

FI Calc is a strong pick for cost-conscious, self-directed planners who want adjustable historical backtesting and CSV exports. Choose it for transparent scenario exploration; choose another planner when tax treatment, required distributions, Monte Carlo probabilities or stricter control over saved-input privacy are essential.