The report
Monthly contribution needed
$3,177
Save this every month for 20 years to retire at 50.
FIRE number
$1,806,111
In 20-yr dollars
In today's dollars
$1,000,000
At 4% withdrawal rate
Annual contribution
$38,128
Over 20 years
Tool · Calculator
The retirement age calculator.
Pick the age you want to retire. The calculator returns the monthly contribution it takes to get there — inflation-adjusted, at your chosen withdrawal rate.
Move the age, move the math.
Fig. 01Every additional year of compounding before retirement reduces the monthly contribution required, nonlinearly. Push retirement age out, or pull it in — see what each year does to the savings burden.
Age 4717 yrs away
$3,915per month
Age 5020 yrs away
$3,177per month
Age 5323 yrs away
$2,625per month
Age 5525 yrs away
$2,327per month
Field note
Time is the cheapest input.
Read the scenario table above. The drop in required monthly contribution between retiring at age X and age X+3is almost always larger than the user expects — sometimes 30–50%. That's because three extra years of compounding work on the entire portfolio, not just incremental contributions.
If the number this calculator returns feels impossible, the cheapest fix is usually time, not income. The second cheapest is lower retirement expenses — at a 4% withdrawal rate, every $1,000 you cut from annual spending removes $25,000 from the FIRE target.
The recommended stack
Tools to get you there.
We may earn a commission if you open an account through these links, at no extra cost to you. We only recommend services we'd use ourselves.
- Compare brokeragesBrokerage
Fidelity or Vanguard
Open a Roth IRA, 401(k) rollover, or taxable brokerage account to house the contributions this calculator says you need.
Why we recommend it: Low-cost index funds keep more of your contributions compounding into retirement.
- Compare HYSAsHYSA
High-Yield Savings
Park your emergency fund and short-term cash where it earns 4-5% APY while you front-load investments.
Why we recommend it: A stable cash buffer means you never sell stocks at the wrong time to cover an emergency.
- Read the reviewBudgeting
Budgeting App
Hit the monthly contribution number this calculator gave you. A budgeting app surfaces leaks and protects the savings line.
Why we recommend it: The required savings rate is binding only if you can actually execute it month after month.
Frequently asked.
§ FAQ01How do I calculate the age I can retire?
Two inputs decide the answer: your FIRE number (annual retirement spending divided by your safe withdrawal rate) and your savings trajectory. This calculator inverts the standard FIRE formula — it asks what monthly contribution gets you there by a target age.
02How much do I need to save monthly to retire by 50?
A 30-year-old with $50K saved targeting $40K of annual retirement spending (a $1M FIRE number at 4%) needs roughly $1,400/month at 7% nominal returns. Required contribution scales nonlinearly with age — every additional year of compounding before retirement dramatically reduces the monthly burden.
03What is the safe withdrawal rate for early retirement?
The Trinity Study (Bengen, 1994) established 4% as a 30-year safe withdrawal rate for traditional retirement. Early retirees with 40-50+ year horizons typically use 3.25-3.5% to account for the longer duration and sequence-of-returns risk.
04Should I use nominal or real returns?
This calculator uses nominal returns and explicitly inflates retirement expenses to future dollars. Use ~7-10% for nominal stock returns and 2-3% for inflation. To reason in today’s dollars, set inflation to 0% and use real returns directly (about 4-5% for stocks).
05What if I can't save the required monthly amount?
Three levers move the math: (1) push retirement age out — the scenario panel shows how much the required contribution drops with 2-5 extra years, (2) lower retirement expenses — every $1K of annual spending cut removes $25K from the FIRE number at 4%, (3) increase income.
Methodology
How this calculator works.
- Inverted FIRE formula
- Standard FIRE solves for when you hit your number given a contribution. This tool solves for the contribution given a target age. Both use the same future-value-of-an-annuity math: PMT = (FV − PV×(1+r)^n) / [((1+r)^n − 1)/r].
- Inflation-adjusted FIRE number
- Retirement expenses are inflated to the target retirement year, then divided by the safe withdrawal rate. The result is a nominal future-dollar FIRE number. Today’s-dollar equivalent is shown separately.
- Monthly compounding, end-of-month
- Returns compound monthly using (1 + annual)^(1/12) − 1. Contributions are applied at the end of each month — slightly conservative versus beginning-of-month contributions.
- No Social Security or pension
- The calculator assumes the portfolio funds 100% of retirement expenses. To model guaranteed income, subtract it from retirement expenses before entering the number.
For the standard direction — what year you reach FIRE at a given savings rate — use the FIRE Calculator. To stress-test the retirement portfolio against bad sequence-of-returns luck, see the Withdrawal Simulator.
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Financial disclaimer
This calculator is for educational and informational purposes only. It does not constitute financial, investment, tax, or legal advice. Past performance is not indicative of future results. Please consult a qualified financial professional (CFP, RIA, or CPA) before making investment decisions. Read our full disclaimer.