API and MCP server

HTTP

Pass values as query parameters. Strings carrying units are parsed the same way the site parses them, so 5ft 11in and 3/8 work.

curl "https://rulecalculators.com/api/calc/board-feet?thickness=1&width=6&length=8"

Returns the value, the formatted string, every intermediate step and the sources for the formula.

Tools beyond the catalogue

A catalogue calculator is a formula over a few numbers. The tools take what a formula cannot — a list, a pay period, an IP address, two time zones — and answer at their own endpoint. 31 of them, listed at /api/tool.

curl "https://rulecalculators.com/api/tool/subnet?address=192.168.1.130&prefix=26"
curl "https://rulecalculators.com/api/tool/statistics?values=4,8,15,16,23,42"
curl -X POST "https://rulecalculators.com/api/tool/paycheck" \
  -H 'content-type: application/json' \
  -d '{"gross":2500,"frequency":"biweekly","filingStatus":"single"}'

Each returns the answer as text with its working and its source, plus the structured data behind it. Comma-separated query values become lists.

MCP

Point any MCP client at the endpoint below and the whole catalog appears as tools. Useful when you want an assistant that does not do arithmetic in its head.

{
  "mcpServers": {
    "calculators": {
      "type": "http",
      "url": "https://rulecalculators.com/api/mcp"
    }
  }
}

Embeds

Each calculator page carries a ready iframe snippet. Embeds are noindex and link back to the source page, so they add a tool to your article without competing with it in search.