Early Retirement Planning Calculator

Early retirement planning uses the same underlying math as traditional retirement but with an aggressive timeline. The approach centers on a portfolio target that can sustain annual expenses at a safe withdrawal rate — a 4% withdrawal rate is common in planning models for 30-year retirements, while 3.5% is often used for 50+ year retirements. These rates produce corresponding portfolio targets based on annual expenses divided by the chosen withdrawal rate.

From current portfolio and monthly contributions, the calculator projects how many years until the portfolio reaches the target. It assumes a consistent return rate (5-7% real return is a common planning assumption) and consistent monthly contribution — real-world results will differ, but the model illustrates directional patterns.

Three factors substantially shift the timeline: savings rate (each unit saved accelerates both accumulation and reduces required portfolio size), expected return (compounds powerfully at long horizons), annual expense target (lower expenses reduce target portfolio proportionally). A 40,000/year retirement requires a portfolio of 40,000 ÷ SWR. A 30,000/year retirement requires a smaller portfolio — a meaningful reduction in time needed.

How to use it

Input current portfolio, monthly contribution, expected real return, planned annual retirement expenses, and safe withdrawal rate. The tool shows years to retirement, target portfolio, and projected annual withdrawal at retirement.

What the result means

Years to retirement is when your portfolio reaches the target that sustains expenses at the safe withdrawal rate. Target portfolio is calculated as annual expenses ÷ SWR. These are projections based on constant return — actual path varies.

Educational FIRE planning tool. Not financial advice.

Quick example

With current portfolio of 100,000 and monthly contribution of 1,500 (plus expected real return of 5% and annual retirement expenses of 30,000), the result is 17.7 years. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Current Portfolio, Monthly Contribution, Expected Real Return, Annual Retirement Expenses, and Safe Withdrawal Rate. The rate and the time horizon typically have larger effects — compounding means a small change in either reshapes the final figure more than a similar shift in contribution size. Test this by doubling one input at a time.

What's happening under the hood

Iterates monthly portfolio growth (current × monthly rate + contribution) until it reaches target (annual expenses / SWR). Uses real return to strip out inflation for true purchasing power. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

The annual review habit

Plug new numbers in every year. Income changes, expenses shift, markets move. A plan that isn't revisited quietly drifts out of date. This tool is cheap to re-run — so re-run it.

What this doesn't capture

Real plans get re-run against new information every year or two. The result here is a reasonable direction, not a destination. It is a starting point for thinking, not a commitment to a specific future.