Safe withdrawal rate calculator
How much can you take out each year so that the money lasts? Test the 4 % rule on any of 60 famous portfolios, in every month of history since 1926.
What this calculator does
You choose a portfolio, a starting sum and the share you take out in the first year, for example 4 %. Every following year the withdrawal grows with inflation, as in William Bengen's study of 1994 that gave the “4 % rule”. The calculator then starts a retirement in every month of history and checks whether the money lasted the whole period.
What the safe withdrawal rate means
For each start it finds the largest first-year withdrawal that would have lasted to the end. The smallest of these numbers is the safe withdrawal rate of the portfolio: the most that worked even for the unluckiest retiree in the data. For a mix of half US stocks and half bonds over 30 years it comes out a little under 4 % on monthly data; the worst starts were in the late 1960s, when high inflation followed.
What you can set
Any of 60 models or a single asset class, the length of retirement from 15 to 50 years, fund costs, rebalancing, and the currency: US dollars since 1926 or euros since 1953.
What it does not count
Taxes, changes in spending, pensions and other income. Real fees can be higher. The past is not a promise: a rate that always worked before can fail in the future. See where the data comes from and the eras.