Retirement Monte Carlo Simulator

How often does a withdrawal rate run out of money? Change any input and 100,000 simulated retirements rerun.

Starting portfolio ($)

Spending in the first year ($)

Withdrawal rate4.0% ($40,000 a year)

Years in retirement30 years

Stocks60% stocks, 40% bonds

Stock average return

Stock standard deviation

Bond average return

Bond standard deviation

Stock–bond correlation

Results

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Failure rate

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Paths that ran out

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Half of failures by year

Returns are real (inflation-adjusted) and drawn from a normal distribution each year.
The portfolio is rebalanced to your stock share every year.
You withdraw at the start of each year. The withdrawal is a fixed share of the starting balance, held constant after inflation.
No fees or taxes.
The default return figures are rounded assumptions, not fitted to data. Model error can move the estimate in either direction.
Every setting uses the same 100,000 market histories, and sampling error is about ±0.2 percentage points.
Only spending as a share of the portfolio changes the failure rate. Doubling both dollar amounts gives the same result.
The withdrawal rate rounds to the nearest 0.05% and stops at 10%.
Real markets crash more often than a bell curve predicts; see Catastrophic Financial Risks.
This is an illustration, not financial advice.