Why this exists
Most retirement calculators answer one question: how much do I need to never work again? That is a fine question, and it is not the one most people are actually asking.
The real questions are messier. Can I stop saving and let it ride? What if I work two days a week instead of five? How do I fund the fourteen years between retiring at 45 and being allowed to touch my 401k? How much can I spend if I am willing to finish at zero rather than leave an estate? And what happens if the market falls apart in my first year?
Each of those has a clean closed-form answer that almost nothing on the internet will compute for you. That is what these are for.
Two conventions that make the numbers meaningful
Everything is in real terms. A projection that says "$4.2m in
thirty years" is useless without knowing what $4.2m buys by then. Every figure here
is in today's money, so it is directly comparable to today's expenses. The real
return is derived using the Fisher relation — (1+n)/(1+i) − 1 — not by
subtracting inflation from returns. At 7% and 3% that is 3.883%, not 4%, and over
thirty years the difference is not small.
Contributions are end-of-year. Money invested during a year does not earn a full year of growth. Assuming otherwise silently adds a year of compounding to every contribution and makes every projection optimistic.
What these projections are worth
They are arithmetic, not forecasts. Each one assumes a constant return every year, which no market has ever delivered. Treat the output as a reference point that tells you roughly where you stand and which levers matter, not as a prediction.
The 4% rule stress test exists precisely because single-return projections are misleading about early retirement. It shows what happens when the same average return arrives in a different order, and the spread is wide enough to change decisions.
How the site is built
Everything runs in your browser. No accounts, no server-side processing, no database. Your figures are saved in your own browser's local storage so they persist between visits, and they are never transmitted to us — see the privacy policy. Retirement calculator inputs are sensitive financial data, and the safest way to handle them is not to receive them.
The formulas are pure functions covered by an automated test suite, verified against closed-form results and cross-checked by independent methods. Where a shortcut would be easier but wrong — subtracting inflation instead of using the Fisher relation, multiplying expenses by years instead of taking a present value — the test suite pins the correct behaviour.
What is here
- Bridge Account Calculator — How much taxable money you need to cover the years before penalty-free retirement access.
- Barista FIRE Calculator — The portfolio you need when part-time work covers part of the bills — health cover included.
- Die With Zero Calculator — The most you can spend each year if the plan is to finish at zero, not preserve principal.
- Coast FIRE Calculator — The number that grows into full FIRE on its own, so you can stop contributing.
- 4% Rule Stress Test — What happens to the same plan when the bad years come first instead of last.
What this is not
We are not licensed financial advisers, and nothing here is a recommendation. These tools cannot see your tax position, risk tolerance, job security or health. They will happily compute a confident-looking number from assumptions that are wrong for you. See the disclaimer for the full position.
Corrections
If you find an error in a formula or an explanation, please report it via the contact page. Corrections ship with a test so they stay fixed, and they are the most useful message you can send.
How the site is funded
The calculators are free and will stay free. The site is supported by advertising and affiliate links, which appear only in clearly labelled blocks kept visually separate from calculator results. A commercial relationship never affects a number this site produces.