Safe withdrawal rate calculator

The withdrawal rate is the first year's withdrawal as a share of the portfolio; the dollar amount then rises with inflation every year. This calculator gives the rate that makes a portfolio last exactly the number of years you choose at a constant return and inflation, and how long a withdrawal you already have in mind would last.

Arithmetic from your own inputs: no statutory data Runs in your browser — nothing you type is sent to this site's servers or to its analytics No sign-up Methodology and data status

Portfolio at retirementYears it must lastNominal return (% a year)Inflation (% a year)Or: first-year withdrawal you have in mind

Withdrawal rate that lasts 30 years: 4.63%
First-year withdrawal: $46,262
$40,000 a year lasts: 37.5 years
Real return assumed: 2.44%

Years	3% return	4% return	5% return	6% return	7% return	8% return
20	5.23%	5.72%	6.23%	6.75%	7.29%	7.85%
25	4.24%	4.74%	5.26%	5.81%	6.39%	6.98%
30	3.57%	4.08%	4.63%	5.20%	5.81%	6.43%
35	3.10%	3.62%	4.18%	4.78%	5.41%	6.07%
40	2.74%	3.27%	3.85%	4.47%	5.12%	5.81%
50	2.25%	2.79%	3.40%	4.06%	4.76%	5.50%

The withdrawal is taken at the start of each year and raised by inflation every year; the balance earns the same return every year and reaches zero exactly at the end of the period. A constant return is the key simplification: real markets deliver the same average with bad years mixed in, and a bad first decade ends a plan early — which is why the 4% rule was derived from historical sequences, not from an average. This page states the rate that constant assumptions imply; the withdrawal calculator adds income sources and taxes.

The link keeps your inputs.

The formula

With a real return g (the nominal return less inflation, compounded: (1 + r)/(1 + i) − 1) and withdrawals at the start of each of n years, the first-year rate that exhausts the portfolio at the end of year n is w = g ÷ [(1 + g)(1 − (1 + g)⁻ⁿ)]. With no real return it is simply 1/n: 3.33% for 30 years. Years remaining for a given first-year withdrawal W and balance B solve the same equation for n.

What a constant return leaves out

Markets do not pay the average every year. Two retirements with the same average return but different orderings end very differently, because withdrawals taken in a downturn sell more shares. That is why the 4% rule (the 4 percent rule) was derived from every retirement start year since 1926 rather than from an average: in Bengen's data it is the rate that lasted at least 30 years even for the worst start year, 1966, whose portfolio ran out after 33 years. Against a constant-return calculation, that worst case corresponds to a real return well below the long-run average. Use this page to see the arithmetic; treat the rate that survives history as the conservative bound.

Statements on this page and their sources

Each sentence below states a fact the calculator does not compute. It was checked against the document named, most recently on 2026-09-10; the date is when to re-read it.

The 4% rule: withdraw 4% of the portfolio in the first year and raise the dollar amount by inflation each year after; in Bengen's data a 4% first-year withdrawal never ran out in less than 32 years with half to three-quarters in stocks, and the worst start year was 1966.
- Bengen, W. P., 'Determining Withdrawal Rates Using Historical Data', Journal of Financial Planning, October 1994 (reprinted March 2004); data 1926–1992, retirements beginning 1926–1976 — Assuming a minimum requirement of 30 years of portfolio longevity, a first-year withdrawal of 4 percent, followed by inflation-adjusted withdrawals in subsequent years, should be safe.
Checked 2026-09-10.
The Trinity study found a 4% inflation-adjusted withdrawal lasted 30 years in 95% of periods with a 50/50 portfolio and 98% with 75% stocks (1926–1995, long-term corporate bonds).
- Cooley, P. L., Hubbard, C. M. and Walz, D. T., 'Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable', AAII Journal, February 1998, pp. 16–21; data 1926–1995 — Table 3 (inflation-adjusted withdrawals): 4% over 30 years — 75% stocks 98%, 50% stocks 95%.
Checked 2026-09-10.
In Bengen's data a first-year rate of about 3.5% lasted at least 50 years in every case, and 3% was 'absolutely safe' to the extent history is a guide.
- Bengen, W. P., 'Determining Withdrawal Rates Using Historical Data', Journal of Financial Planning, October 1994 (reprinted March 2004); data 1926–1992, retirements beginning 1926–1976 — an 'absolutely safe' (to the extent history is a guide) initial withdrawal level is 3 percent
Checked 2026-09-10.

Questions this page answers

What is the 4% rule?

Withdraw 4% of the portfolio in the first year of retirement and raise the dollar amount by inflation each year after. In Bengen's 1994 study (retirements beginning each year from 1926 to 1976, half to three-quarters in stocks and the rest in intermediate-term Treasuries), a 4% first-year withdrawal raised with inflation never ran out in less than 32 years. The Trinity study (1926–1995, with long-term corporate bonds) found the same rate lasted 30 years in 95% of periods with a 50/50 portfolio and 98% with 75% stocks. It is a historical finding about worst cases, not a guarantee, and it assumes 30 years, no taxes or transaction costs, and spending that changes only with inflation.

Is 4% safe for 40 or 50 years?

Less so. At a constant 5% return and 2.5% inflation the rate that lasts exactly 40 years is about 3.85% and for 50 years about 3.40%; in Bengen's own data a first-year rate of about 3.5% lasted at least 50 years in every case.

How much do I need to get $2,000 a month?

$2,000 a month is $24,000 a year. At a 4% first-year rate that takes $600,000; at the 4.63% that a constant 5% return and 2.5% inflation give for 30 years, $518,788. Both figures are before tax; Social Security or a pension reduces what the portfolio must supply.