TL;DR
Our safe withdrawal rate is the highest fixed initial percentage that survives 95% of historical cohorts at your specified horizon and allocation. Below it, almost no plan fails; above it, multiple historical periods would have broken.
In short
The 95% threshold is a convention. Higher thresholds (99%) give a lower safe rate; lower thresholds (75%) give a higher one. We default to 95% because that's the academic standard from Bengen onwards, but the choice is yours.
We're working on a full deep-dive for this article — including historical data, charts, and worked examples. In the meantime, you can run a free simulation to explore the underlying numbers yourself.
Frequently asked questions
- Why 95% and not 100%?
- 100% survival in 155 years means calibrating to the worst-ever sequence, which is so conservative it leaves enormous money on the table for the typical retiree. 95% is the standard compromise.
- Does the safe rate include investment fees?
- No — it's gross of fund and platform costs. Subtract your actual all-in costs (typically 0.15-0.5% for DIY) from the displayed rate to get your true take-home safe rate.
Stress-test your own FIRE plan
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