FI Calc review
A free web calculator for comparing retirement withdrawal strategies through historical backtesting.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
FI Calc is a free, web-based retirement calculator for people evaluating whether a portfolio and withdrawal plan may sustain retirement spending. It uses historical-data backtesting and supports retirement duration, portfolio allocation, annual withdrawals, income, and extra withdrawals. Users can compare strategies including Constant Dollar, Percent of Portfolio, and 1/N. The tool is intended for planning analysis rather than financial advice, making it a fit for people who want to explore historical scenarios without paying for software.
Its modeling covers equities, bonds, and cash, with controls for rebalancing and glide paths. Income inputs include Social Security and pensions, and extra withdrawals can be configured by timing and duration. FI Calc reports outcomes such as portfolio sustainability across historical market conditions, and calculation results can be exported. Those features make it useful for comparing how different spending and allocation choices behaved in past periods; the results are not a forecast of future performance.
The main limitation is tax treatment: FI Calc does not automatically estimate taxes, and its documentation says taxes should be included in withdrawal amounts. The product is described as free and donation-supported, with no paid tier specified in its published plan details. Choose it if you want a no-cost way to compare withdrawal strategies, income assumptions, and portfolio configurations using historical data. It is less suitable if tax-aware projections are central to your planning or you need a tool positioned as financial advice.
FI Calc pros and cons
- Where it wins
- Compare Constant Dollar, Percent of Portfolio, and 1/N withdrawal strategies
- Model Social Security, pension income, and extra withdrawals
- Configure allocation, rebalancing, and glide paths; export results
- Where it doesn't
- Does not automatically estimate taxes; taxes should be included in withdrawals
- Focused on planning analysis, not financial advice
- Historical backtests compare past market conditions, not future outcomes
FI Calc fact sheet, pricing and score →
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