Safe Withdrawal Rate Calculator

Where the 4% rule came from

The figure traces to work in the 1990s testing withdrawal rates against historical US market returns over 30-year retirements. Four percent of the starting portfolio, raised each year with inflation, survived every historical window tested. That is the whole claim, and it is narrower than the way the number now gets used.

It was a US-only study, over 30 years, on a particular stock and bond mix, before fees. Retire at 50 and the money has to last far longer than 30 years. Hold a different mix, or pay a percentage-of-assets fee, and the safe rate moves.

This tool does not assume 4%. It takes your inputs and finds the highest rate that survives your horizon, which is usually the more useful number to have.

Why the answer is so sensitive to the return you assume

Withdrawals and returns pull in opposite directions on the same balance, so small changes to either compound quickly. On a $1,000,000 portfolio over 30 years at a 4% real return, the highest sustainable rate works out around 5.5%, and a 4% withdrawal finishes with roughly $910,000 still invested.

Drop the return assumption and that headroom disappears fast. This is why a single headline percentage means little without the assumptions attached. Run your own number at a return a point or two below what you expect, and treat that as the planning figure.

The limitation that matters most

This model uses a constant return. Real markets do not deliver one, and the order in which returns arrive changes the outcome even when the average is identical. Two retirees with the same thirty-year average can finish in completely different places depending on which decade the bad years landed in.

A poor first five years while you are withdrawing does damage a good later decade cannot repair, because the withdrawals sold shares at the bottom. That is sequence of returns risk, and it is the largest gap between this calculator and reality. Run the sequence tool alongside this one.

The maximum rate, for common combinations

Two inputs decide almost everything: the real return and how long the money has to last. This is the highest rate that still finishes above zero, calculated the same way the tool does.

What that table says about the 4% rule

Read across the 30-year column and 4% looks comfortable. Even at a 3% real return the ceiling is 4.9%, so the conventional figure carries roughly a fifth of headroom above it.

Now read the 40-year column, which is what an early retirement actually needs. At a 3% real return the ceiling drops to 4.2%. The 4% rule still passes, but the margin has almost gone, and that is before any tax or platform fee.

This is the honest reason the rule attracts so much argument. It is not wrong. It was derived for a 30-year horizon, and people apply it to horizons it was never tested against. Lengthen the retirement or lower the return and it stops being conservative.

Why the withdrawal is fixed, and what flexibility buys

This model takes the same amount every year in real terms, whatever the market did. That is the standard assumption and it is deliberately unforgiving, because it removes the one thing real retirees actually do, which is spend less when things look bad.

Even modest flexibility changes the arithmetic, because the damage comes from selling assets during a decline. Skipping an inflation increase in a bad year, or trimming discretionary spending, leaves more invested to recover. A retiree willing to adjust can support a meaningfully higher starting rate than this tool shows.

So treat the number here as the floor rather than the forecast. If you can flex, you have more room than it says. If your spending is genuinely fixed, this is the right model and you should use the conservative end of it.

Common questions

Is the 4% rule still valid?

It was always a finding from a specific historical study rather than a rule. It remains a reasonable starting point for a 30-year US retirement in a low-fee portfolio. For longer retirements, higher fees, or non-US portfolios, run your own numbers rather than inheriting the figure.

Should I use a real or nominal return?

A real return, after inflation. This calculator raises your withdrawal with inflation each year, so the return has to be expressed in the same terms or the two are inconsistent and the result flatters you.

What about tax?

Not modelled. Withdrawals from taxable or tax-deferred accounts are generally taxable, so the gross amount you need to withdraw is higher than your spending. Add your expected rate on top of the withdrawal figure.

How long should I plan for?

Longer than you expect to live. Planning to a life expectancy means roughly half the outcomes run out of money. Thirty years is conventional for retirement at 65; retiring earlier needs forty or more.

Does a higher withdrawal rate work if I stay flexible?

Generally yes. Trimming spending in bad years, even modestly, raises the sustainable rate meaningfully because it stops you selling into a decline. This model assumes you never adjust, which is the conservative case.

How is this different from the sequence of returns tool?

This asks whether an average return supports a withdrawal rate. The sequence tool asks what happens when the same average arrives in a bad order. You want both answers before committing to a rate.

Does the portfolio have to end at zero?

That is what this tool solves for, and it is the aggressive reading. If you want to leave an inheritance, or simply want a margin, pick a rate below the maximum. The table above shows how much you give up: at a 4% real return over 30 years, moving from the 5.5% ceiling down to 4% is the difference between finishing at zero and finishing with most of the portfolio intact.

Should I include Social Security or a pension?

Not in the portfolio value. Subtract them from your annual spending instead, and apply the withdrawal rate to what is left. Guaranteed income reduces the amount the portfolio has to produce, which is a different thing from increasing the portfolio.

What real return should I assume?

Lower than you would like. A globally diversified equity portfolio has historically returned somewhere around 5% real over long periods, and a mixed stock and bond portfolio less. Whatever you use, run the table one row lower as well and check you would still be comfortable.