I started Arithnote as a lightweight place for my own notes and short-form writing. There was a moment where I had to copy and paste a lot between spreadsheets and a text doc, so I thought - I only need simple calculations, why not do it right in text? As I added the features I needed and polished the experience, Arithnote became a computational notepad: you write normally, and it evaluates calculations, variables, percentages, units, currencies, and totals inline. I made a point of keeping it as lightweight as possible (open-and-write), otherwise I'd just use a full-featured document editor. Cross-device sync was important to me, but I didn’t want note contents stored as readable plain text, so they’re end-to-end encrypted before syncing. Hopefully, it will be useful for others who like to work in a simple text editor but need cross-device sync, and who regularly switch between a notepad and calculator. Markdown support and a few theme choices as a bonus. I’d especially value feedback on whether calculations feel natural in everyday notes, what Arithnote doesn’t handle well yet, and what’s still missing.

Arithnote

The calculator that lives inside your notes.

The calculator that lives inside your notes.