# FIRE Calculator – Financial Independence, Retire Early

URL: https://speedycalculator.com/calculators/finance/fire-number/
Last updated: 2026-10-25

> The FIRE calculator works out your FIRE number – the portfolio that can cover your expenses forever at a safe withdrawal rate – and how many years until you reach financial independence based on your savings, income, expenses and investment return.

## Inputs

- Current age
- Annual take-home income
- Annual expenses
- Current investments
- Expected return (nominal) (%)
- Inflation (%)
- Safe withdrawal rate (%)

## Results

- FIRE number
- Annual savings
- Savings rate
- Years to financial independence
- Age at financial independence
- Lean FIRE (expenses × 0.75)
- Fat FIRE (expenses × 1.5)

## Formula

```
FIRE number = annual expenses ÷ withdrawal rate (25 × expenses at 4%)
Annual savings = income − expenses
Years to FI = log((FIRE + S/r) ÷ (portfolio + S/r)) ÷ log(1 + r), r = real return
```

## Explanation

Your savings rate matters more than anything: saving 50% of income reaches FI in about 17 years at a 5% real return, while saving 10% takes over 50. The 4% rule comes from the Trinity study of 30-year retirements; early retirees often use 3–3.5%.

### How to use the FIRE Calculator – Financial Independence, Retire Early

- **Current age**
- **Annual take-home income**
- **Annual expenses**
- **Current investments**
- **Expected return (nominal)**
- **Inflation**
- **Safe withdrawal rate**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter your current age, annual take-home income, annual expenses, current investments, expected return, inflation and withdrawal rate.

### Tips

- Use your real spending from bank statements rather than guesses.
- Automate savings so they happen before you spend.
- Revisit your plan once a year or after any big life change.
- Keep an emergency fund before investing for long-term goals.

### Common mistakes to avoid

- Underestimating irregular expenses such as car repairs, gifts and annual bills.
- Ignoring inflation for long-term goals.
- Taking on high-interest debt to fund wants.

### Inputs explained

FieldWhat to enterCurrent ageA numberAnnual take-home incomeAmount in your currencyAnnual expensesAmount in your currencyCurrent investmentsAmount in your currencyExpected return (nominal)In %InflationIn %Safe withdrawal rateIn %

### What each result means

- **FIRE number** = [Annual expenses]÷([Safe withdrawal rate]÷100)
- **Annual savings** = [Annual take-home income] - [Annual expenses]
- **Savings rate** = [Annual savings]÷[Annual take-home income]×100
- **Age at financial independence** = [Current age] + [Years to financial independence]
- **Lean FIRE (expenses × 0.75)** = [Annual expenses]×0.75÷([Safe withdrawal rate]÷100)
- **Fat FIRE (expenses × 1.5)** = [Annual expenses]×1.5÷([Safe withdrawal rate]÷100)

### Example values

How the main result changes when **Current age** changes and everything else stays at the example values above:

Current ageFIRE number151,125,00022.51,125,000301,125,00037.51,125,000451,125,000601,125,000

## Worked example

Inputs — Current age: 30; Annual take-home income: $80,000; Annual expenses: $45,000; Current investments: $60,000; Expected return (nominal): 7 %; Inflation: 3 %; Safe withdrawal rate: 4 %.

Results — **FIRE number = $1,125,000.00**; Annual savings = $35,000.00; Savings rate = 43.75 %; Years to financial independence = 19.6; Age at financial independence = 50; Lean FIRE (expenses × 0.75) = $843,750.00; Fat FIRE (expenses × 1.5) = $1,687,500.00.

## FAQ

**What is the FIRE number?**
The portfolio size at which investment income covers your expenses – usually 25 × annual expenses.

**Is the 4% rule safe for early retirement?**
For 40–50+ years, 3–3.5% is more conservative.

**What are Lean and Fat FIRE?**
Retiring on a frugal or a generous budget.

**What formula does the FIRE Calculator – Financial Independence, Retire Early use?**
FIRE number = annual expenses ÷ withdrawal rate (25 × expenses at 4%).