Calcgrid documentation

Open calculator engine for AI agents and people: finance, health, math, unit conversion, physics, chemistry, statistics and everyday calculators, each available as HTML, Markdown, JSON API, MCP tool and A2A skill.

What this service does

Calcgrid computes 184 documented formulas (finance, health, fitness, math, geometry, statistics, unit conversion, physics, chemistry, everyday life, food, construction). Every calculator returns structured JSON with inputs, outputs, units, formula, sources, freshness and next actions. All tools are read-only and deterministic; there are no write actions, accounts or payments.

Guides

API reference — endpoints, parameters, envelopes, versioning
Response format — the unified success/error envelope, timestamps, provenance, cache and next_actions
Errors — error codes, HTTP status codes, retry semantics
Rate limits — fair-use limits and headers
MCP server — connecting with Model Context Protocol clients, tool list
A2A agent — Agent Card, message/send, tasks/get

Calculators by category

Complete list: all calculators · machine-readable: https://tttkmbb.com/api/v1/calculators

Discovery files

llms.txt: https://tttkmbb.com/llms.txt (short) · https://tttkmbb.com/llms-full.txt (everything)
OpenAPI 3.1: https://tttkmbb.com/openapi.json · https://tttkmbb.com/openapi.yaml
ARD manifest: https://tttkmbb.com/.well-known/ard.json
A2A Agent Card: https://tttkmbb.com/.well-known/agent-card.json
MCP server card: https://tttkmbb.com/.well-known/mcp-server-card.json
Sitemap: https://tttkmbb.com/sitemap.xml · robots: https://tttkmbb.com/robots.txt
Service status: https://tttkmbb.com/api/v1/status

Quick start

Find a calculator: GET https://tttkmbb.com/api/v1/search?query=mortgage
Read its schema: GET https://tttkmbb.com/api/v1/calculators/mortgage-payment
Calculate: GET https://tttkmbb.com/api/v1/calculate/mortgage-payment?home_price=400000&down_payment=80000&annual_rate_percent=6.5&term_years=30
Follow next_actions in the response for related calculations.

Markdown source: /docs.md