Time Value of Money Solver

Solve for any one of PV, FV, PMT, N, or rate given the other four TVM variables.

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

Parameters

Parameter	Type	Required	Description
`solve_for`	string	required	Which variable to solve for One of: pv, fv, pmt, n, rate
`pv`	number	optional	Present value
`fv`	number	optional	Future value (default 0)
`pmt`	number	optional	Payment per period
`n`	number	optional	Number of periods
`rate`	number	optional	Rate per period as a decimal

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": "tvm", "arguments": {"solve_for": "pv"}}}'

Or plain HTTP

curl -s https://wingmanprotocol.com/tools/tvm \
  -H 'Content-Type: application/json' \
  -d '{"solve_for": "pv"}'

Try it live

Edit the JSON and run it — this POSTs to https://wingmanprotocol.com/tools/tvm 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).