FIRE Number Calculator

FIRE Number is evaluated from Annual Expenses, Safe Withdrawal Rate and Current Portfolio Value. The calculation reports Your FIRE Number, Amount Still Needed and Estimated Years to FIRE.

Results

Thanks — we’ve logged this for review.

About the FIRE Number Calculator

FIRE Number is treated here as a quantitative relation between Annual Expenses, Safe Withdrawal Rate, Current Portfolio Value and Monthly Savings and Your FIRE Number, Amount Still Needed and Estimated Years to FIRE.

The calculator uses a custom php logic configuration. Each reported value is read as a direct evaluation of the stored rules with the declared field formats and units.

Formula basis:
FIRE Number = Annual Expenses / (Withdrawal Rate / 100)
With the standard 4% rule: FIRE Number = Annual Expenses x 25
Solve n where: Current_Savings x (1+r)^n + Monthly x [(1+r)^n - 1]/r = FIRE_Number
Where r = monthly return = annual_return / 12 / 100

Interpret the outputs in the order shown by the result fields. Optional inputs affect only the outputs that depend on those variables.

Formula & How It Works

The calculation applies the following relations exactly as recorded in the metadata:

FIRE Number = Annual Expenses / (Withdrawal Rate / 100)
With the standard 4% rule: FIRE Number = Annual Expenses x 25
Solve n where: Current_Savings x (1+r)^n + Monthly x [(1+r)^n - 1]/r = FIRE_Number
Where r = monthly return = annual_return / 12 / 100

Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.

Worked Examples

Example 1: Standard Middle-Class FIRE

Inputs

annual_expenses: 60000 withdrawal_rate: 4 current_savings: 150000 monthly_savings: 3000 expected_return: 8
Your FIRE Number: $1,500,000. Amount Still Needed: $1,350,000. Estimated Years to FIRE: 27.3 years

With Annual Expenses = 60,000, Safe Withdrawal Rate = 4, Current Portfolio Value = 150,000 and Monthly Savings = 3,000 as the stated inputs, the result is Your FIRE Number = $1,500,000, Amount Still Needed = $1,350,000 and Estimated Years to FIRE = 27.3 years. Each value corresponds to the declared output fields.

Example 2: Lean FIRE — Frugal Lifestyle

Inputs

annual_expenses: 30000 withdrawal_rate: 4 current_savings: 500000 monthly_savings: 2000 expected_return: 9
Your FIRE Number: $750,000. Amount Still Needed: $250,000. Estimated Years to FIRE: 5.5 years

With Annual Expenses = 30,000, Safe Withdrawal Rate = 4, Current Portfolio Value = 500,000 and Monthly Savings = 2,000 as the stated inputs, the result is Your FIRE Number = $750,000, Amount Still Needed = $250,000 and Estimated Years to FIRE = 5.5 years. Each value corresponds to the declared output fields.

Example 3: Fat FIRE — Affluent Lifestyle

Inputs

annual_expenses: 120000 withdrawal_rate: 4 current_savings: 500000 monthly_savings: 8000 expected_return: 10
Your FIRE Number: $3,000,000. Amount Still Needed: $2,500,000. Estimated Years to FIRE: 22.3 years

With Annual Expenses = 120,000, Safe Withdrawal Rate = 4, Current Portfolio Value = 500,000 and Monthly Savings = 8,000 as the stated inputs, the result is Your FIRE Number = $3,000,000, Amount Still Needed = $2,500,000 and Estimated Years to FIRE = 22.3 years. Each value corresponds to the declared output fields.

Example 4: Conservative Long Retirement (3.5% SWR)

Inputs

annual_expenses: 75000 withdrawal_rate: 3.5 current_savings: 300000 monthly_savings: 4000 expected_return: 7
Your FIRE Number: $2,142,857. Amount Still Needed: $1,842,857. Estimated Years to FIRE: 24.5 years

With Annual Expenses = 75,000, Safe Withdrawal Rate = 3.5, Current Portfolio Value = 300,000 and Monthly Savings = 4,000 as the stated inputs, the result is Your FIRE Number = $2,142,857, Amount Still Needed = $1,842,857 and Estimated Years to FIRE = 24.5 years. Each value corresponds to the declared output fields.

Common Use Cases

  • Find your FIRE target portfolio size
  • See how annual expenses impact retirement readiness
  • Calculate years to FIRE from current savings