FIRE & Retirement Calculator

The target is annual spending divided by a withdrawal rate. The default rate is 4%. Current savings, new savings each year or month, and an expected real annual return then produce the years to reach that target. Returns are real, meaning inflation-adjusted. The 4% rule is a historical US rule of thumb, not a guarantee.

How it's calculated

The target

Financial independence here means a portfolio large enough that the withdrawal rate covers one year of spending. At 4%, the target is 25 times annual spending.

Formula

Target = annual spending / withdrawal rate

Annual spending: What you would withdraw in a year, in today’s money.
Withdrawal rate: Share of the target withdrawn in the first year. The default is 4% (0.04).

Years to reach it

Savings grow at a constant real annual return r. A contribution C is added at the end of each year. The page solves that compound-growth formula for the number of years until the balance equals the target.

Years = ln((target + C / r) / (savings + C / r)) / ln(1 + r)

When the return is zero

A zero real return does not grow the balance. The years are the gap divided by what you save each year:

Years = (target − savings) / C

Monthly savings

Monthly savings use the monthly rate that matches the same effective annual real return, (1 + r)^(1/12) − 1. The contribution is added at the end of each month. The result is converted back to years.

Already there, or never

If current savings are already at least the target, the result is already financially independent, in zero years.

If the savings and the return you entered can never reach the target, the page says the goal is unreachable. That happens, for example, when you add nothing and the real return is zero or negative while savings are still short of the target.

Assumptions

The return is a constant real (inflation-adjusted) rate, so spending stays in today’s money and is not inflated again. The 4% rule is a historical US rule of thumb from retirement research. It is not a promise that a portfolio will earn that return or that the money will last.

Fees, taxes, contribution caps, and the order in which returns arrive are not modeled. Reaching the target is not itself a withdrawal plan. The figure is for learning, not financial, investment, or tax advice.

Questions

How is the FI target calculated?

The target is annual spending divided by the withdrawal rate. At the default 4% rate, the target is 25 times one year of spending.

What is the 4% rule?

It is a historical US rule of thumb from retirement research: some past portfolios could support withdrawing about 4% of the starting balance, then adjusting that amount for inflation, over a long retirement. It is not a guarantee of future returns, and it is not a promise that the money will last.

Are the returns adjusted for inflation?

Yes. Enter a real return, already adjusted for inflation. Spending is in today’s money. The page does not apply a second inflation rate on top.

How are the years calculated?

The page solves the compound-growth formula for the number of years until current savings plus new savings reach the target. Contributions are added at the end of each year, or each month if you choose monthly savings. A zero real return is the gap divided by what you save. Monthly savings use a monthly rate that matches the same annual real return.

What if I am already financially independent, or the goal is unreachable?

If savings are already at least the target, the result is already financially independent, in zero years. If the contributions and return can never close the gap, the page says the goal is unreachable instead of showing a year.

What does the calculator leave out?

Fees, taxes, contribution limits, and a poor sequence of returns are not included. Hitting the target is not a plan for how to withdraw the money. This is not financial, investment, or tax advice.

Related guides

Your FIRE number and the 4% rule: how to calculate it, and where it breaks