How long will my money last?

$
$
It lasts
16 yr 1 mo

at 4% real growth, in today's money

The forever line
$1,637/mo
at or under this, it never runs out
Lasts 16 yr 1 mo16 yr 1 mo

The pot, month by month, drawing $3,500 a month. The dot is the last month.

Adjustments

A $500k pot drawn at $3,500 a month lasts 16 yr 1 mo at 4.0% real growth. Drawing $1,637 a month or less, it never runs out.

How to use this, and the parts people get wrong
  • It runs your pot down month by month at the spending you enter, against the return and the inflation you enter.
  • The date it hits zero moves much further on a small change in spending than on a big change in return. Try both and see.
  • It assumes a steady return. Real markets do not deliver one, which is why the date is a guide and not a promise.

The cliff between years and forever

At $3,500 a month the pot lasts 16 yr 1 mo. Draw $500 less and it lasts 20 yr 2 mo; at or under $1,637/mo it never runs out.

$1,637/mothe forever line on this pot and growth
$1,667/mothe 4% convention on this pot

The withdrawal ladder

Same pot and growth; only the monthly draw changes. Your draw is marked.

Drawing / monthThe pot lastsWithdrawal rate
$2,00043 yr 7 mo4.8% of the pot / yr
$2,50027 yr 2 mo6.0% of the pot / yr
$3,00020 yr 2 mo7.2% of the pot / yr
$3,50016 yr 1 mo8.4% of the pot / yr
$4,00013 yr 6 mo9.6% of the pot / yr
$5,00010 yr 2 mo12.0% of the pot / yr
$6,0008 yr 2 mo14.4% of the pot / yr

Questions people ask

How long will my money last?
Drawing $3,500 a month from $500k at 4% real growth: 16 yr 1 mo. The same pot lasts forever at or under $1,637 a month, which is the number that matters most on this page.
Why can money last forever?
When the monthly draw is no more than the monthly growth, the pot replaces what you take. Above that line, every extra dollar drawn shortens the runway twice over: it leaves, and it stops earning.
Is this in today's money?
Yes. The growth figure is real (after inflation) and the withdrawal holds its purchasing power, so "17 years" means seventeen years of the life you priced.
How does this relate to the 4% rule?
The 4% convention draws $1,667 a month from this pot. It is built to survive about 30 years of bad luck, so it sits well below the forever line in most markets.
What should I do if the runway is too short?
The three levers are the draw, the growth and the pot, and the first is the only one under your hand this month. The table above prices each notch of it.

Method and sources

  • Standard drawdown arithmeticMonthly simulation to zero
The calculation

The pot compounds monthly at your real growth rate and the withdrawal leaves monthly. The answer is when the balance first reaches zero; the forever line is the draw at which growth exactly replaces it.

What these figures do not cover
  • Steady real growth is assumed; a bad early sequence shortens real runways.
  • Taxes on withdrawals depend on your accounts and country.
  • Durations past 60 years are shown as 60+ rather than pretended precise.

Last updated July 2026.

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