Finance

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FIRE Calculator.

Plan financial independence with inflation-adjusted spending and return assumptions

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Set your values

Results update as you type.

Your Situation

Market Assumptions

4.8%to FIRE

FIRE Number (Today)

$1,050,000

Current Portfolio

$50,000

$0$1,050,000

Timeline

38

Estimated time to FIRE: 37.1 years (445 months)

Estimated FIRE age: 67.1

Sustainable Monthly Income

$10,657

per month

Goal Corpus

$3,189,620

inflation-adjusted

Fast Track

Monthly Needed for 15-Year FIRE

$4,744

FIRE in

15 yrs

  • Future expense targets are inflated monthly using your inflation assumption.
  • Returns are modeled as a constant monthly compounding rate for planning purposes.
  • Withdrawal rate is a planning assumption and not a guaranteed safe rate.

FAQs

What is a FIRE number?

Your FIRE number is the portfolio size needed for your annual expenses divided by your safe withdrawal rate.

Why account for inflation?

Inflation increases future living costs. Your target corpus should grow accordingly to maintain purchasing power.

What withdrawal rate should I use?

Many people use 4% as a starting point, but a safer rate depends on your risk tolerance, retirement length, and market conditions.

Cite this calculator

Canonical URL: https://mathify.one/zh/finance/fire

Cite as: Mathify. (2026). FIRE 计算器. https://mathify.one/zh/finance/fire

Use Cases

Estimate your FIRE timeline

Input your current savings, annual spending, and expected returns to see how many years until you can retire early.

Example: If you save $30k/year and spend $40k, with 7% returns, you might reach FI in 15 years.

Compare different return scenarios

Adjust return and inflation assumptions to see how conservative or aggressive your plan is.

Example: Lowering returns from 7% to 5% could add several years to your timeline.

Frequently Asked Questions

What does the FIRE calculator do?
It helps you estimate how long it will take to achieve financial independence by considering your spending, savings, and assumed investment returns, all adjusted for inflation.
How does inflation affect my FIRE plan?
Inflation reduces purchasing power over time. The calculator adjusts your spending and savings growth to reflect real returns, giving a more realistic timeline for financial independence.
What is the 4% rule in FIRE?
The 4% rule suggests you can safely withdraw 4% of your portfolio annually in retirement. This calculator uses your return assumptions to model similar withdrawal sustainability.

Tips & Common Mistakes

Tips

  • Use realistic inflation rates (2-3%) to avoid overestimating future purchasing power.
  • Consider your spending changes in retirement; healthcare and travel may differ.
  • Revisit your assumptions annually as your savings and expenses evolve.
  • Remember that returns are not guaranteed; use conservative estimates for safety.

Common Mistakes to Avoid

  • Ignoring inflation and using nominal returns, which overstates growth.
  • Assuming constant spending without accounting for lifestyle changes.
  • Using overly optimistic return rates that don't reflect market volatility.

Last updated: August 13, 2026