Notepad Calculator

Notepad Calculator is a smart calculator disguised as a notepad. Instead of juggling a calculator app and a notes app, just write what you're thinking — every line is calculated instantly, right next to your words.

Write math the way you think

Type expressions in plain language and get answers on the same line:

500 + 200 * 3 → solved as you type, no equals button needed
10 km in miles, 5 feet 6 inches + 8 in
today + 3 weeks, Jan 1 2025 to Mar 1 2025
tax = 15% then reuse price + tax anywhere below
8%, VAT, tip, subtotals and totals with #tag aggregation

Every answer becomes a variable you can reference later, so multi-step calculations stay readable.

Powerful, all offline

A fast local engine handles a huge range of math with no internet, accounts, or AI required:

Functions: sqrt, sin, cos, tan, log, ln, exp, abs, round, max, min, pow, and more
Constants: pi, tau, phi, e
Units & conversions: length, weight, volume, time, speed, temperature, electrical, and custom units
Currency conversion with offline-cached exchange rates and a live "Update Rates" refresh
Statistics, percentages, bases & bitwise (hex/binary/octal), trig in degrees or radians
Chinese large-number support (万 / 亿) and spelled-out numbers (million, billion)

Make it yours

Definition Sheet — define global variables, your own units (1 box = 12 items), and custom functions (f(x) = x * 2) that apply to every document
Organize work into folders, pin, archive, and search across all notes
Headers (# Title), dividers (---), and tag totals keep long sheets tidy
Tint the results column, align answers, and adjust line spacing to taste
Export any sheet to Markdown or CSV

Built for Mac

Menubar Quick Calc — pop open an instant calculator from the status bar without leaving your work
iCloud sync — your notes and calculations follow you to iPhone and iPad
Native Mac storage, autosave, and a clean three-pane layout (sidebar · editor · live results)
Smart autocomplete for units, currencies, functions, and variables
10 interface languages with live switching

Whether you're estimating a project budget, converting recipes, planning a trip, or just splitting a bill, Notepad Calculator turns your notes into a living spreadsheet — without the spreadsheet.