How to use the early retirement calculator
- Enter your Current age and Annual spending in retirement in today's dollars. Spending sets both your FIRE number and how much you must save.
- Fill in Current savings and investments and Annual savings, meaning what you actually invest each year, not your income.
- Set the Expected real return after inflation (%). Use 5% to be cautious or 6 to 7% for the long-run US stock average. The inflation calculator converts a nominal return.
- Pick a Withdrawal rate (%): 4% is the classic rule, and 3 to 3.5% suits a 40-year retirement.
- Add the Traditional retirement age (for Coast FIRE), usually 65, then read FIRE number, Time to FIRE, Retire at age and Coast FIRE number today.
How the FIRE number and timeline are calculated
Your FIRE number is annual spending divided by the withdrawal rate, so 4% means 25 times your spending. The rule comes from the Trinity Study, which tested 15 to 30 year payouts. The timeline grows your balance month by month: multiply by (1 + r)1/12, add one twelfth of your annual savings, and repeat until you reach the FIRE number (see compound interest). The Coast FIRE number is the FIRE number divided by (1 + r)years to your traditional retirement age. The same math drives the Mr. Money Mustache table: from zero at 5% real, saving 10% takes 51 years and 50% takes about 16.
Worked example with the default numbers
A 30-year-old spends $50,000 a year, has $50,000 invested, saves $25,000 a year (a 33% savings rate) and uses a 5% real return and 4% withdrawal rate. The FIRE number is $50,000 ÷ 0.04 = $1,250,000. The tool shows 23 years 6 months, so retirement at 53 and 6 months. The Coast FIRE number is $1,250,000 ÷ 1.0535 = $226,613, which is $176,613 more than the $50,000 saved. At a 7% return the plan takes 20 years. At a 3.5% withdrawal rate the target becomes $1,428,571 and the wait 25 years 5 months.
Limits and edge cases
- Returns are steady here, but a bad market early in retirement can sink a plan that works on average.
- Taxes on withdrawals, Social Security, pensions and health insurance before Medicare at 65 are not modeled, so include them in your spending. Savings also stay flat, without raises.
- Withdrawals from a 401(k) or IRA before age 59½ usually carry an extra 10% tax unless an exception applies. The 2026 IRS limits are $24,500 for 401(k) deferrals and $7,500 for IRAs; the 401(k) retirement calculator shows their effect.
- If you already have enough, or cannot reach the target within 100 years, the tool says so instead of showing a number.
Early retirement FAQ
How much do I need to retire early?
Divide yearly spending by your withdrawal rate. At 4%, $50,000 of spending needs $1,250,000; at 3.5% it needs $1,428,571. Lower spending shrinks the target and raises what you can save.
What is the 4% rule?
Withdraw 4% of your starting portfolio in year one, then raise that dollar amount with inflation. In the Trinity Study, mostly stock portfolios lasted 30 years at that rate.
Is 4% still safe for early retirement?
It was built for 30 years. Morningstar's 2026 base case is 3.9% for 30 years, and retirements of 40 to 60 years usually call for 3 to 3.5%. Spending less after market drops helps.
How many years until I reach FIRE?
Mostly your savings rate. From zero at 5% real and a 4% rate, saving 10% takes about 51 years, 50% takes 16 years 5 months and 75% takes 7 years 1 month.
What is Coast FIRE?
It means your invested money alone will grow to your FIRE number by a traditional retirement age, so you only need to cover current expenses. With the default numbers that is $226,613 today.
Sources: IRS 2026 limits; IRS early distributions; Trinity Study (1998); Morningstar 2026.