FIRE Number Calculator

Financial-independence target from annual expenses and a safe withdrawal rate, plus lean/fat variants and years to reach it.

Free tier eligible — 500 calls/month with a free key from /pricing; x402 pay-per-call above quota.

Parameters

Parameter	Type	Required	Description
`annual_expenses`	number	required	Expected annual spending in retirement, USD
`withdrawal_rate`	number	optional	Safe withdrawal rate as a PERCENT (default 4)
`current_savings`	number	optional	Current invested savings in USD
`annual_contribution`	number	optional	Amount invested per year in USD
`expected_return`	number	optional	Expected annual return as a PERCENT (default 7)
`inflation`	number	optional	Annual inflation as a PERCENT (default 0)

Call it over MCP (JSON-RPC 2.0)

curl -s https://wingmanprotocol.com/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": {"name": "fire_number", "arguments": {"annual_expenses": 100}}}'

Or plain HTTP

curl -s https://wingmanprotocol.com/tools/fire_number \
  -H 'Content-Type: application/json' \
  -d '{"annual_expenses": 100}'

Try it live

Edit the JSON and run it — this POSTs to https://wingmanprotocol.com/tools/fire_number from your browser.

This tool is x402-metered — agents pay per call with USDC on Base. The 402 response below is the standard x402 payment-requirements envelope: sign the EIP-3009 authorization and retry with the X-Payment header, or get a free key at /pricing (500 calls/month, no card, no crypto).