Everything a back-of-napkin calc should be
One window. Type on the left, answers on the right.
Live answers
Every line evaluates as you type. Mix notes and math freely. Plain text just stays as notes.
Syntax highlighting
Numbers, units, keywords and functions are colour-coded, and every variable gets its own colour.
Variables
rent = 1200, then use rent anywhere below. Reference sum, average and prev too.
Plain-language percent
15% of 80, 50 + 18%, 20% off 50, 50 is what % of 200.
Units
Length, mass, time, volume, data, temperature, area and speed, like 100 km/h in mph or 1 GB in MB.
Live currency
Real exchange rates plus crypto, like $50 in EUR or 0.1 btc in usd. Cached for offline.
Dates & time zones
today + 30 days, today to christmas, 3pm New York to London.
Functions
sqrt, min/max, average, plus finance: compound(), mortgage().
Library & folders
Keep many calculations, organise them in folders, and a 30-day Trash for anything you delete. Autosaves.
Export
Send any calculation to CSV, Markdown, HTML or PDF with one shortcut (⌘E).
Local-first
Your calculations live on your devices, and in your own iCloud with Pro. No sign-up, no account, nothing to leak.
Native everywhere
Built in SwiftUI for Mac, iPhone and iPad. Fast, light, and at home on each.
Questions
- Is Jotsum free?
- Yes. The calculator is free to download and use. Every download also gets 30 days of Pro with no card. After that, Pro is $29 once, $9.99 a year, or $0.99 a month, and one purchase covers your Mac, iPhone and iPad.
- Does it sync between my Mac and iPhone?
- Yes, with Pro. Your sheets sync through your own iCloud. There's no account and nothing is stored on our servers.
- Does it work offline?
- Yes. Exchange rates are the only thing Jotsum fetches, and it keeps the latest ones for when you're offline.
- What can I type?
- Things like 15% of 80, $50 in EUR, 100 km/h in mph, today + 30 days, or 3pm New York to London. Name a number once and reuse it on any line below.
- How is it different from Soulver?
- Soulver has been around longer and does more. Jotsum costs less and starts free. Here they are side by side.
Get Jotsum
Free on the App Store. One app for Mac, iPhone and iPad, and Pro bought on one covers all three. Every download starts with 30 days of Pro, no card needed.