What is the work-optional (FIRE) number?

The portfolio size at which your investments can cover your spending indefinitely — commonly 25 times your yearly spending, which is the 4% withdrawal rule written the other way around.

How much do I need to retire on $4,000 a month?

At a 4% withdrawal rate you need about $1.2 million ($48,000 × 25). Social Security or a pension covering part of that spending shrinks the target dollar for dollar — $2,000 a month of Social Security halves it.

What return should I assume for retirement planning?

A common planning setup is 6–8% nominal for a diversified portfolio minus about 2.5–3% inflation — a real return of 4–5%. Planning in today's dollars with a real return keeps the target meaningful.

Work-Optional Number Calculator — When Work Becomes a Choice

Spending when work is optional

Invested already

Investing monthly

Yearly return

Add what applies to you:

Advanced settings

Inflation, %/yr

What builds your number

The math, line by line

Your road to optional

Your portfolio in today’s dollars, growing at your real return. The dashed line is the target. Hover any year.

What moves the date

How we calculate

What is included

The target is the yearly spending your portfolio must cover (spending minus Social Security or pension) divided by your withdrawal rate — the classic “25× your spending” when the rate is 4%. Growth is compounded monthly at your real return: the return you enter minus inflation, so everything stays in today’s dollars and the target does not silently rot.

What is estimated or left out

A planning estimate, not advice. Markets do not grow in a straight line — the order of good and bad years matters (sequence risk), which is why many people use 3.5% instead of 4% for very early retirement. Taxes on withdrawals depend on account types (Roth vs traditional vs brokerage) and are not modeled; neither are advisor fees. Social Security is counted from day one — if it starts later than your date, you will need a bridge.

The formula, in plain words

number = (monthly spending − Social Security) × 12 ÷ withdrawal rate
real return = your return − inflation
each month: portfolio = portfolio × (1 + real return ÷ 12) + monthly investing
your date  = the month the portfolio first reaches the number

Common questions

Why 25 times my spending?: That is the 4% rule flipped around: if you withdraw 4% of a portfolio per year, the portfolio must be 100÷4 = 25 times your yearly spending. At a 3.5% rate it is about 29×; at 5%, 20×. The chip above lets you pick.
Is the 4% rule safe?: It survived every 30-year period in US history when it was tested (the Trinity study), but the future is not the past, and very early retirees need the money to last 50+ years, not 30. That is why 3.25–3.75% is the common choice for long horizons — and why “work-optional” beats “never work again”: even small income moves the math a lot.
Should I count my house?: Not the one you live in — it does not pay your grocery bill. But a paid-off house lowers your monthly spending, which lowers the target by 25× every dollar saved. Killing a $1,500 mortgage payment cuts the number by $450,000.

The Work-Optional Number