FIRE Number Calculator
Translate an annual spending gap and your withdrawal-rate assumption into an illustrative capital target. Compare assumptions without calling any rate safe.
Your inputs
Use consistent units and periods. Defaults are examples.
Your result
Check the assumptions below before relying on a result.
Formula and method
Annual gap=max(0, spending−other income). Target=annual gap/(entered withdrawal rate/100). The target is expressed in the same purchasing power as the inputs.
Worked example
With annual spending 48,000, other income 12,000 and an assumed 4% rate, the annual gap is 36,000 and the implied target is 900,000. At 3.5% the same gap implies 1,028,571.43; at 4.5%,800,000. These rates are examples, not recommendations.
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Open calculator ↗How to use this result
- Use one currency throughout. An annual spending input is not a monthly amount.
- Read the timing, inflation and fee definitions before comparing scenarios.
- Inspect the annual table and download CSV to retain the assumptions.
- Use the second scenario on supported tools to vary one assumption at a time. No result proves that stopping work is prudent.
Questions about this calculation
Does this identify a safe withdrawal rate?
No. The rate is entered by you. Dividing spending by it is arithmetic; it does not establish a sustainable rate or probability of funding a retirement.
What if other income exceeds spending?
The modeled portfolio spending gap and target are zero. The model does not invest the income surplus. Progress divided by a zero target is shown as not defined.
Is a zero shortfall enough to stop working?
No. This model omits uncertainty, exceptional spending and access restrictions. Review the assumptions and a separate withdrawal scenario before interpreting the number.
Continue your calculation
Compare, save and share assumptions
Scenario A uses the original inputs above. Scenario B has independent inputs below. Optional Save stores numeric inputs only in this browser. Links disclose the inputs you choose to include: use illustrative values.