# how long will my money last

Dec 4, 2022

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here’s a formula you can type into a spreadsheet to see how long your money will last.

`=NPER(4%,yearly_spending,-principal)`

for instance, if you spend 100k a year, then a 2m$ principal lasts 41 years. so if you think you’ll live no more than 41 years longer, a 2m$ is all you need.

whereas if you use the standard 4% rule (aka 25x rule), then you need 2.5m$ to retire if you spend 100k.