Size a nest egg as annual spend ÷ safe withdrawal rate, show the gap, and estimate years to financial independence at a constant real return and savings rate.
| Nest egg | – |
| Gap | – |
| Years to FI | – |
Use this FIRE calculator for a Trinity-style sketch: the pile that would support your spending at a chosen withdrawal rate, then how long constant real returns and yearly savings take to get there. The 4% rule is research, not a guarantee. Sequence-of-returns risk is ignored.
Nest egg = annual spend ÷ SWR. Gap = max(0, nest − invested now). Years are found by looping: each year the portfolio grows at the real return and then receives that year’s saving, up to 80 years. 999 means the target was not reached (or you save nothing and have no compounding pile).
Annual spend: What you expect to spend in retirement, in today’s money.
SWR (%): Safe withdrawal rate, e.g. 4 for 4%.
Invested now: Current invested assets (not the house you live in unless you will sell it).
Save / year: New money added to the portfolio each year.
Real return (%): Expected return after inflation.
Nest egg: Target portfolio = spend / SWR.
Gap: How much more you still need invested.
Years to FI: Whole years until the nest egg is reached, or 999.
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