What is a FIRE Calculator?
A FIRE (Financial Independence, Retire Early) calculator computes your target net worth needed to retire and never work again, based on your annual spending and the 4% safe withdrawal rate. It also shows how many years until you reach that number given your current savings rate and investment return assumptions.
The 4% Rule and FIRE Number
FIRE Number = Annual Expenses × 25 (based on 4% withdrawal rate)
Years to FIRE ≈ depends on savings rate — see table below
- LeanFIRE: Retiring on a very frugal budget (under $40,000/year). FIRE number = ~$1M. Requires significant lifestyle minimalism.
- Regular FIRE: Retiring with a comfortable middle-class lifestyle ($50,000–$80,000/year). FIRE number = $1.25M–$2M.
- FatFIRE: Retiring with an affluent lifestyle ($100,000+/year). FIRE number = $2.5M+.
- Coast FIRE: Saving enough early that investments compound to your FIRE number by traditional retirement age without additional contributions — then "coasting" with a lower-stress job.
- Barista FIRE: Retiring from a high-stress career but doing part-time work to cover basic expenses, letting investments grow for later.
Is the 4% rule still valid?
The 4% rule originated from the 1994 Trinity Study and was based on historical US market returns. With current bond yields higher than the 2010s, the rule may be more sustainable than some critics suggested. However, for 40–50+ year retirements (typical for FIRE retirees), some planners suggest using 3–3.5% to increase safety. A dynamic withdrawal approach — spending 4% in good market years and 3% in down years — improves sustainability significantly.
What is the impact of savings rate on years to FIRE?
Savings rate is the most powerful lever in FIRE planning. At a 10% savings rate, it takes ~43 years to retire. At 25%: ~32 years. At 50%: ~17 years. At 75%: ~7 years. This relationship is non-linear because a higher savings rate simultaneously builds wealth faster AND reduces the annual spending target (lower spending = smaller FIRE number required). Increasing savings rate from 10% to 50% cuts the retirement timeline by more than half.
How does sequence of returns risk affect FIRE?
Sequence risk is the danger that poor investment returns early in retirement permanently deplete your portfolio even if long-term average returns are fine. A 30% market crash in Year 2 of retirement forces you to sell assets at low prices to fund living expenses, leaving less principal to recover. Mitigation strategies: maintain 1–3 years of expenses in cash/bonds (bucket strategy), consider flexible withdrawal amounts tied to portfolio performance, and have a contingency plan (part-time work) for sustained bear markets.
Last Updated: March 2026 · For US audiences