Percentage Calculator

Percent-of, percent change, is-what-percent, increase/decrease and reverse-percent.

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

Parameters

Parameter	Type	Required	Description
`mode`	string	required	Which calculation to run One of: percent_of, is_what_percent, percent_change, increase, decrease, reverse_percent
`percent`	number	optional	Percent value (percent_of/increase/decrease/reverse_percent)
`base`	number	optional	Base value (percent_of/increase/decrease)
`part`	number	optional	Part value (is_what_percent)
`whole`	number	optional	Whole value (is_what_percent)
`from_value`	number	optional	Starting value (percent_change)
`to_value`	number	optional	Ending value (percent_change)
`total`	number	optional	Total after the percent was added (reverse_percent)

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": "percentage", "arguments": {"mode": "percent_of"}}}'

Or plain HTTP

curl -s https://wingmanprotocol.com/tools/percentage \
  -H 'Content-Type: application/json' \
  -d '{"mode": "percent_of"}'

Try it live

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