Learn TrueCalc

Welcome! This guide teaches you spreadsheet formulas and TrueCalc from zero — you do not need to have ever opened a spreadsheet. Chapters arrive as the corresponding features ship:

• Foundations — formulas, values and types, functions, cell references, error codes, and why you must choose a dialect (Google Sheets vs Excel).
• Workbooks — workbooks, worksheets and cells; saving a workbook as JSON.
• Advanced — recalculation, circular references, arrays and spill, reproducibility and volatile functions.
• Platforms — the browser and Node, MCP for AI agents, and the hosted API.

A first taste

Every code example in this guide is executed against the pinned @truecalc/core package on every CI run — if an example breaks, the build fails. Here is one:

import { createEngine } from '@truecalc/core';
import assert from 'node:assert/strict';

// Engines are always created for an explicit conformance target.
const engine = createEngine('google-sheets');

// ABS returns the absolute value of a number.
// Fixture: google_sheets/math.tsv — "absolute value of negative integer"
const result = engine.evaluate('=ABS(-26)', null);
assert.deepEqual(result, { type: 'number', value: 26 });

Formula examples are tested too:

=ABS(-26) // => 26

(Expected values come from the Google Sheets conformance fixtures in truecalc/core — this guide never asserts spreadsheet behavior that has not been verified against a real spreadsheet.)