How long until I retire?
We calculate your real retirement number from your spending and safe withdrawal rate, then simulate your investments year by year to find your retirement age.
Frequently asked questions
How is my 'retirement number' calculated?
We take your desired annual retirement spending, subtract what Social Security is expected to cover for the year (12 times your monthly estimate), and divide what's left by your safe withdrawal rate. At a 4% withdrawal rate, $60,000 in spending minus $0 of Social Security gives a target of $1,500,000 — the amount your portfolio needs to hold before you can retire.
What is a safe withdrawal rate and why does 4% matter?
Your safe withdrawal rate is the share of your portfolio you plan to spend each year in retirement without running out of money over a multi-decade retirement. 4% comes from historical research (the 'Trinity study' and its successors) showing a 4% first-year withdrawal, adjusted for inflation thereafter, has historically survived 30-year retirements in most market conditions. It's a widely used starting point, not a guarantee — some people use 3% to be more conservative, or 5% if they're comfortable adjusting spending in down years.
Should I use a nominal or 'real' (inflation-adjusted) return rate here?
Use a real (inflation-adjusted) return, which is why the default is 5% rather than a nominal market average closer to 8-10%. Because your spending target and contributions are already entered in today's dollars, feeding in a real return keeps the whole projection in today's purchasing power — so the number you land on is directly comparable to your current cost of living.
What if I don't know my future Social Security benefit?
Check the box marked 'not sure / skip Social Security' and we'll calculate your number using $0 of Social Security income, which is the more conservative assumption. You can always come back and enter an estimate later — you can get a projected benefit amount for free from your Social Security statement at ssa.gov.
What happens if I won't reach my number by age 100?
We'll show you the gap between your projected balance at 100 and your target, framed as something to act on rather than a dead end. The three levers that close the gap are contributing more each month, lowering your planned retirement spending, or aiming for a higher (though less certain) rate of return — try adjusting any of the inputs above to see how much each one moves your retirement age.