What Is a Retirement Number?
Your retirement number is the total portfolio value you need to retire comfortably. It's the single figure that answers "do I have enough?"
Last updated: Aug 2026
Quick answer
A retirement number is the portfolio value needed to fund annual spending in retirement. A common estimate is spending divided by withdrawal rate: for example, $50,000 per year divided by 4% equals $1.25 million. Social Security or pension income lowers the number because your portfolio covers only the remaining gap.
The basic formula
If you want to spend $50,000 per year and use the classic 4% withdrawal rate, you need $1.25 million. Change either variable and the number changes with it.
What goes into the number
Annual spending
How much you plan to spend each year in retirement. This is the most important input. Include housing, food, healthcare, travel, taxes, everything. Most people underestimate this, especially healthcare and taxes.
Withdrawal rate
The percentage of your portfolio you withdraw each year. The classic 4% rule is a starting point, but your actual safe rate depends on time horizon, market conditions and flexibility. Learn more about SWR →
Other income sources
Social Security, pensions, rental income or part-time work reduce the amount your portfolio needs to cover. If Social Security provides $20,000/year, your portfolio only needs to fund the remaining $30,000, dropping your number from $1.25M to $750,000.
Time horizon
Retiring at 45 means your money needs to last 40-50 years, not 30. Longer horizons generally need a lower withdrawal rate or a larger number.
Why a single number isn't enough
A retirement number gives you a target, but it doesn't tell you:
- Whether you'll actually reach it at your current savings rate
- How it holds up if markets crash early in retirement (sequence risk)
- Whether your withdrawal strategy is sustainable over different market conditions
- What happens if inflation runs higher than expected
That's why stress-testing matters. A number is a starting point; a plan that survives bad markets is the real goal.
How RetireNumber helps
- Calculate your number from desired spending and withdrawal rate
- Project when you'll reach it across multiple return scenarios
- Run 1,000 Monte Carlo simulations to test the odds
- Backtest against 95+ years of real market history
Next step: run your numbers
Use the free retirement number calculator to get your target instantly, then stress-test your retirement plan across historical and Monte Carlo scenarios.