TrueCalc is a formula engine with exact Google Sheets semantics — embed it in Rust applications, run it in any JavaScript runtime, or give AI assistants direct formula access.
Most formula engines are either incomplete (50–100 functions) or GPL-licensed, making them a non-starter for closed-source products. TrueCalc ships 484 functions, conformance-tested case by case against real Google Sheets — not a spec interpretation — under an MIT license. The evaluator is stateless: bring your own data model, call evaluate, get a result.
Fintech and insurance teams embed truecalc-core directly in Rust pricing engines and policy calculators. They wire their own data model to the evaluator — no workbook, no spreadsheet — and get correct IRR, PMT, and NPV results without building or maintaining the formula logic themselves.
Web and backend developers reach for @truecalc/core when their application needs user-authored formulas: calculated fields in a SaaS product, formula-driven pricing rules, or a headless formula service. The WASM package runs in Node.js, Bun, Deno, and the browser — no server required.
AI practitioners install truecalc-mcp and connect it to Claude Desktop or any MCP-compatible client. Their AI assistant can evaluate, validate, and batch-process formulas without writing any code — useful for financial analysis, data wrangling, and anywhere LLMs would otherwise hallucinate on arithmetic.
- truecalc-core — Rust: stateless formula evaluator, bring your own data model
- @truecalc/core — WebAssembly: formula evaluation in any JavaScript runtime
- truecalc-mcp — MCP server: formula tools for AI assistants
- Learn — core concepts and getting started
- Function Reference — all 484 functions with examples
- MCP API — tool reference for AI integrations
Full documentation → docs.truecalc.app