# FI Calc

Twelve withdrawal strategies replayed against every US market cycle since 1871.

*https://stockmarketstack.com/tools/ficalc · Retirement & FIRE Calculators*

## Facts

### At a glance

| Field | Value |
| --- | --- |
| Vendor | FI Calc |
| Category | Retirement & FIRE Calculators |
| Job | retirement |
| Website | https://ficalc.app |
| Pricing model | free |
| Free tier | true |
| Open source | false |
| Licence | none |
| Self-hosted | false |
| Tested hands-on | false |
| Last updated | 2026-09-14 |

### Pricing

| Tier | USD | Period |
| --- | --- | --- |
| Free | 0 USD | month |

### Coverage

| Field | Value |
| --- | --- |
| Asset classes | stocks, bonds |
| Markets | us |
| Works outside the US | false |
| Data latency | none |
| Platforms | web |
| AI features | none |

### Interfaces

| Field | Value |
| --- | --- |
| API | false |
| Webhooks | false |
| Scripting | none |
| Python | false |
| Spreadsheet add-in | false |
| MCP server | false |
| Export | csv |

### Capabilities

Yes: backtesting

No: charting, screening, scanning, automation, live_trading, paper_trading, portfolio_tracking, broker_import, tax_reporting, alerts, news, options_analysis

*Verified: pricing 2026-09-13; capabilities 2026-09-13; coverage 2026-09-13.*

## What it is

FI Calc takes one retirement plan — a portfolio value, a length, an allocation and a withdrawal
rule — and replays it against every overlapping historical window of that length since 1871, then
counts how many of those runs still had money at the end. The default plan ($1,000,000 over 30
years, 80/15/5 stocks/bonds/cash, $40,000 a year, Constant Dollar) runs 125 cycles and returned a
96.8% success rate on 13 September 2026.

The withdrawal strategies are why you would pick it over the other free historical-cycle
calculators. Twelve are offered, grouped in the dropdown by what they are after:

- **Basic** — Constant Dollar, Percent of Portfolio, 1/N
- **Maximize spending** — Variable Percentage Withdrawal (VPW), Dynamic SWR
- **Maximize longevity** — Endowment Strategy, Guyton-Klinger, 95% Rule, CAPE-based, Sensible
  Withdrawals, Hebeler Autopilot II, Vanguard Dynamic Spending

Each exposes its own parameters instead of a single rate. Guyton-Klinger is the clearest example:
you set the initial withdrawal, the guardrail bands (by default, when the withdrawal rate runs 20%
above or below the initial rate) and the adjustment applied when a band is hit (10% each way), then
toggle the modified withdrawal rule and whether the rules are ignored for the final fifteen years.
Vanguard Dynamic Spending takes a rate with a ceiling and a floor, 4%/5%/2.5% by default.
CAPE-based takes a base rate plus a weight on the CAPE earnings yield. Dynamic SWR takes an ROI and
an inflation assumption; VPW takes your age at retirement, and a custom-parameters checkbox turns
it into CVPW with an explicit discount rate. A minimum annual withdrawal ($20,000) is on by
default across the variable strategies, and a maximum is available.

An Explore Strategies button opens a short survey that narrows the twelve down for you.

## Pricing

Free, with nothing to buy: no account, no login, no paid tier. The footer asks for donations
through a Gumroad link.

## Data & coverage

It forecasts nothing — every path in the output actually happened. The series are Robert Shiller's: S&P 500
prices and dividends from January 1871 (Cowles and associates before 1926), the 10-year US Treasury
yield for bonds, and US CPI for inflation. Cash uses no historical data at all — you supply a fixed
growth rate, 1.5% by default. Everything is US and everything is annual: the withdrawal happens on
1 January, fees, growth and dividends are applied on 31 December, and rebalancing comes last.

Beyond the withdrawal rule you can set per-sleeve expense ratios, a rebalancing frequency in
years, a glide path to a different final allocation, any number of income streams and one-off
extra withdrawals, and a restricted range of history to run against.

The bundle served on 14 September 2026 carries 154 annual rows, 1871 through 2024 — the real
edge of the dataset.

## Integrations

Nothing goes in: no import, no API, no spreadsheet add-in and no account, and the privacy policy
says what you type never leaves the device. Two things come out — **Download as CSV**, offered
once for all simulations and again inside any single simulation you open, and **Save or Share**,
which encodes the whole configuration into a link and copies it to the clipboard. The author
calls that link an early preview and reserves the right to break old ones. The page carries
Google AdSense and Analytics, and the CSV button fires its own analytics event: the numbers stay
local, the fact that you exported them does not.

## Limitations

- **No taxes, no account types, no RMDs.** One pot of money. You gross up your own spending figure.
- **The success rate is not a probability.** The 30-year windows overlap heavily and share most of
  their years, so 125 cycles are not 125 independent trials. There is no Monte Carlo mode in the
  interface.
- **US only, and the data stops at 2024.** No international equity or bond series at any setting,
  and 2025 had not been added as of 14 September 2026 — later than the site's own stated schedule.
- **The documentation has fallen behind the app.** The guide's What's New page ends in August 2023,
  its footer reads 2023, and its page on how dividend yields are derived still says "coming soon".
- **Closed source, one person, limited support.** There is no public repository for the calculator,
  and the contact page warns that email replies cannot be guaranteed.

## Alternatives

[cFIREsim](https://stockmarketstack.com/tools/cfiresim) is the closest comparison — the same Shiller-based cycle method, plus a gold sleeve and
richer income modelling, but fewer spending plans. FIRECalc is the original and the plainest.
[Boldin](https://stockmarketstack.com/tools/boldin) is the paid answer for anyone who needs tax, account types and Roth conversions modelled
rather than approximated.

Compare it against the rest of the [retirement calculators](https://stockmarketstack.com/categories/retirement-planning).

## FAQ

### Is FI Calc still maintained?

It runs, but it has slowed. The build serving the app on 14 September 2026 carries the same hashed bundle filename as the Internet Archive's capture of 13 February 2026, and a different one from the capture of 16 January 2026 — so a release did ship in early 2026 and nothing has shipped in the seven months since. The guide's What's New page stops at 26 August 2023, and the data still ends in 2024. The site says data for a given year is normally added in the second half of the following year, which puts 2025 data about three months overdue.

### Does FI Calc model taxes, account types or Social Security?

No taxes and no account types. There is one undifferentiated portfolio of equities, bonds and cash, with no taxable, tax-deferred or Roth distinction and no RMDs; the guide tells you to add your expected tax bill to your withdrawal figure yourself. Social Security, pensions and rental cashflow are modelled, but only as generic Income streams with a start year, a duration and an inflation switch.

### Can I save or export a FI Calc run?

Yes, two ways, neither of which involves an account. Every run has a Download as CSV button — for all simulations at once or for a single simulation you have opened — and a Share Calculation button that encodes the whole configuration into a URL you can bookmark or send. The author labels the URL feature an early preview and reserves the right to break old links, though the guide records that none have broken so far.

### What historical data does FI Calc use?

Robert Shiller's dataset, running from January 1871 — S&P 500 prices and dividends (Cowles data before 1926), the 10-year US Treasury yield for bonds, and US CPI for inflation. The app ships it as 154 annual rows, 1871 through 2024, embedded in the JavaScript bundle rather than fetched. Cash is the exception, because it uses no historical series at all — you supply a fixed annual growth rate, defaulting to 1.5%.

## Also worth comparing

- [cFIREsim](https://stockmarketstack.com/tools/cfiresim.md) — Run a withdrawal plan against every market cycle since 1871 and count how many survived.
- [Boldin](https://stockmarketstack.com/tools/boldin.md) — A year-by-year US retirement model — accounts, taxes, Social Security, Medicare, housing.
- [FIREproof](https://stockmarketstack.com/tools/fireproof.md) — The cFIREsim author's second simulator, with the taxes and accounts the first one lacks.
- [ProjectionLab](https://stockmarketstack.com/tools/projectionlab.md) — Model a whole financial life as milestones and cash flows, then run it against history.
- [Backtest by Curvo](https://stockmarketstack.com/tools/curvo.md) — Backtest a portfolio of European UCITS funds on index data reaching back to 1970.
- [Portfolio Charts](https://stockmarketstack.com/tools/portfolio-charts.md) — Any asset allocation, charted since 1970 in twelve countries' currencies and inflation.

## Named as a replacement for

- [Portfolio Visualizer](https://stockmarketstack.com/alternatives/portfolio-visualizer.md)