Version 7.0.8

Every way to install TrueCalc.

One engine on npm, JSR and crates.io. 491 Google Sheets functions plus 27 timezone extensions of our own. Every command below was run before it was written down.

Run it here · @truecalc/core

FormulaVariables

Runs the published package in this tab. Nothing is sent anywhere.

Press Run to evaluate.

That is the published package running in your browser — the same artifact npm install gives you. Try ="10" + 5, or =TEXT(DATE(2026,13,1), "yyyy-mm-dd").

JavaScript & TypeScript

WebAssembly. Runs in the browser, Node and Deno — no server, no network.

npm

npm install @truecalc/core

Node 24+ — on Node 22 run with `--experimental-wasm-modules`. Bundlers need a WASM plugin: vite-plugin-wasm for Vite, `experiments.asyncWebAssembly` for webpack 5.

Documentation →@truecalc/core on npm

JavaScript & TypeScript

import { evaluate, list_functions } from '@truecalc/core';

evaluate('SUM(A1, B1)', { A1: 100, B1: 200 });
// => { type: 'number', value: 300 }

evaluate('IF(A1 > 0, "yes", "no")', { A1: 1 });
// => { type: 'text', value: 'yes' }

list_functions().length;
// => 518

Rust

The engine itself. Stateless, no allocator surprises, bring your own data.

cargo

cargo add truecalc-core

Errors are values, not `Err` — a division by zero returns `Value::Error(ErrorKind::DivByZero)`, exactly as a cell would.

Documentation →truecalc-core on crates.io

Rust

use std::collections::HashMap;
use truecalc_core::{Engine, Value};

let engine = Engine::sheets();

let mut vars = HashMap::new();
vars.insert("A1".to_string(), Value::Number(100.0));
vars.insert("B1".to_string(), Value::Number(200.0));

let result = engine.evaluate("=SUM(A1,B1)", &vars);
assert_eq!(result, Value::Number(300.0));

MCP server

Give Claude, Cursor or any MCP client a calc engine it cannot get wrong.

cargo

cargo install truecalc-mcp

Twelve tools over stdio, including a stateful workbook your agent can keep across a whole conversation.

Documentation →truecalc-mcp on crates.io

MCP server

// claude mcp add truecalc -- ~/.cargo/bin/truecalc-mcp
// …or write it yourself, in .mcp.json:
{
  "mcpServers": {
    "truecalc": {
      "type": "stdio",
      "command": "/Users/you/.cargo/bin/truecalc-mcp"
    }
  }
}

Deno

On JSR, and the only runtime that needs no permission flags at all.

deno

deno add jsr:@truecalc/core

No --allow-net, no --allow-read. The engine is compiled into the module graph, so `deno run` is the whole command.

Documentation →@truecalc on JSR

Deno

import { evaluate, createEngine } from '@truecalc/core';

evaluate('=SUM(A1,A2)', { A1: 10, A2: 20 });
// => { type: 'number', value: 30 }

createEngine('google-sheets').evaluate('=UPPER("ok")', {});
// => { type: 'text', value: 'OK' }

@truecalc/workbook

A whole workbook in the browser — sheets, a dependency graph, and recalc.

npm

npm install @truecalc/workbook

On Node, hand `init()` the wasm bytes directly — Node cannot fetch a file:// URL. See the workbook-node example in the repo.

Documentation →@truecalc/workbook on npm

@truecalc/workbook

import init, { JsWorkbook } from '@truecalc/workbook';

await init();

const wb = new JsWorkbook('sheets');
wb.addSheet('Sheet1');
wb.set('Sheet1', 'A1', '10');
wb.set('Sheet1', 'A2', '=A1*2');

// The context pins NOW, TODAY and RAND, so the same workbook
// plus the same context is always the same grid.
wb.recalc(JSON.stringify({ timestamp_ms: 0, timezone: 'UTC', rng_seed: 0 }));

// resolved() hands back a JSON string, not an object.
JSON.parse(wb.resolved('Sheet1', 'A2'));
// => { type: 'number', value: 20 }

truecalc-workbook

The same workbook, in Rust. Canonical JSON in, canonical JSON out.

cargo

cargo add truecalc-workbook

Serializes to RFC 8785 canonical JSON, which is what makes a workbook byte-comparable across languages and across years.

Documentation →truecalc-workbook on crates.io

truecalc-workbook

use truecalc_workbook::{
    Address, CellInput, EngineFlavor, RecalcContext, Value, Workbook, Worksheet,
};

let mut wb = Workbook::new(EngineFlavor::Sheets);
wb.add_sheet(Worksheet::new("Budget")).unwrap();

let a1 = Address::from_a1("A1").unwrap();
let a2 = Address::from_a1("A2").unwrap();
let a3 = Address::from_a1("A3").unwrap();

wb.set("Budget", a1, CellInput::Literal(Value::Number(1000.0))).unwrap();
wb.set("Budget", a2, CellInput::Literal(Value::Number(500.0))).unwrap();
wb.set("Budget", a3, CellInput::Formula("=SUM(A1:A2)".to_string())).unwrap();

// RecalcContext::new(unix_ms, iana_tz, rng_seed)
let ctx = RecalcContext::new(1_780_000_000_000, "Etc/GMT", 0).unwrap();
wb.recalc(&ctx);

assert_eq!(wb.get("Budget", a3).unwrap().value(), &Value::Number(1500.0));

Not yet

What you cannot install today.

Listed so you can plan around it. Neither of these has an install command because neither exists yet — when they ship, they will appear above with the rest.

The full roadmap, with nothing dressed up →

Python

In development

Native bindings for notebooks and data pipelines.

In development. The bindings build from source in the repo, but nothing is published to PyPI yet — so there is no install command to give you.

Hosted API & MCP

In development

Workbooks that outlive the request, reachable from anywhere, with no infrastructure of yours.

Not yet shipped. Everything above runs entirely on your machine, with no account and no network.

Something not working?

A result that disagrees with Google Sheets is a bug, not a limitation. Open an issue with the formula and we will add it to the conformance corpus.

Open an issue Read the docs