Run-Calc

A fast desktop calculator that feels like a notepad, not a form. Windows and Mac. Local-first, with optional AI.

Run-Calc: Calculate at the Speed of Thought

Run-Calc is a high-speed desktop calculator for Windows and Mac that empowers you to calculate the way you think. Designed to feel like a natural notepad rather than a rigid form, it allows you to jot down notes, stack equations line by line, and get instant answers exactly where you type them. Whether you are performing quick analysis or detailed planning, Run-Calc keeps your momentum high by delivering inline results the moment you press Enter.

Why Choose Run-Calc?

⌨️Calculate Naturally: Type expressions naturally — like 42 + 3 * 4 - 5 * ( 2 + sin(3 + 2 * pi / 2) ) — and get results instantly without searching for a keypad.
❓Ask questions: ?? what is the speed of light in nautical miles per second? (😊 161874.97 nautical miles per second)
⚡Fluid Momentum: Start any new line with +, -, *, or / to automatically continue calculating from your previous result.
🛠️Powerful Data Tools: Use variables to store values and pipelines to filter, map, or sum lists of data step-by-step.
🎨Personalized Themes: Switch between built-in Dark, Light, and High Contrast modes, or install any community-made theme directly from the Open VSX registry.
🤖AI (BYOK): Connect your own AI provider to ask complex questions or generate ready-to-run calculation lines.
🚀Lightweight Performance: Enjoy an ultra-lean footprint that stays out of your way while you work.
📖Readable by Design: Calculations stay in plain text, making your work easy to scan, revisit, and share as notes.
🔒Local-First Privacy: Your worksheets and settings stay securely on your machine, ensuring your data remains private.

Type naturally. Press Enter. Get instant answers inline.

Desktop app for everyday math, planning, and quick analysis

Easy calculate

Basic arithmetic

Any conversions (AI powered)

AI powered conversions

Run-Calc lets you calculate the way you think. Write one line after another, keep your notes, and see results exactly where you typed the expression.

See how it works Manage worksheets View shortcuts Browse functions Set up BYOK

Why people like Run-Calc

No button hunting: just type expressions like 2+3*4 and press Enter.
Keep momentum: start next line with +, -, *, or / to continue from the last result.
Local-first and practical: your worksheet and settings stay on your machine.
Optional AI (BYOK): you choose provider and key only if you want it.

Readable by design

Calculations stay in plain text, so your work is easy to scan, revisit, and share as notes.

Beginner-friendly

In-app help stays short and clear. Deeper guides and details live on this site when you need more.

Powerful when needed

Variables, pipelines, math functions, themes, and precision controls are ready as your work grows.

Explore the docs

Operations: expression syntax, variables, comments, functions, and AI flow.
Worksheets: create, switch, rename, close, and save encrypted worksheet tabs.
Shortcuts: keyboard commands to work faster with less friction.
Functions: grouped reference for all functions exposed in Run-Calc.
AI key Setup: where to create API keys for each provider and what to paste into Run-Calc.
What's New: latest improvements and behavior updates.
Privacy: data handling summary, policy, and legal links.

Expression Engine

Run-Calc expression parsing and evaluation are powered by Expr language.

GitHub

Run-Calc on GitHub — source code, releases, and issue tracker.