Arithmos
Arithmos
iPhone · iPad · Mac
Write the way you think — “€350 in USD”, “20% of 4,200”, “June 9 + 5 weeks”. Arithmos reads each line and lays the answer right beside it, live, as you type.
Calculate as you type
Every line is its own little calculation. Give values names and reuse them, drop in a percentage, or just write a sentence — Arithmos finds the number and keeps a running total at the bottom of the sheet.
cabinets = $4,20030% of 800=== and a live document total
Currencies & units
Live exchange rates for dozens of currencies, plus length, mass, time and
data-size units — all with a natural in. Mix them with your
figures and the conversions just happen.
$500 in EUR · £99 in JPY5 kg in lb · 1 mile in km2 hours in minutes · 1.5 gb in mb
Money over time
Ask for compound growth, mortgage repayments or hourly earnings in plain English — Arithmos works out the figure right beside the line.
$10,000 after 5 years at 4%interest on $10,000 for 5 years at 4% compounding monthly5,212 for 6 months at 8%/monthmonthly repayment on $300,000 over 30 years at 6%$75/hour × 80 hours
Notes that add up
Structure a sheet like a real note. Turn any list into a table with a single tap, total a table’s columns, tick off checklists as you go, and render headings and links inline. It’s a calculator and a notepad at once.
===- [ ] / - [x][links](…) & PDF export
Tag & total by colour
Tap any line number in the gutter to tag it — it cycles through four colours, and a fifth tap clears it. The moment a line is tagged, the footer adds a running total for each colour, so income, expenses, or any grouping you like add up on their own.
Eight themes
Every theme restyles the editor, the syntax colors, and the typeface. Tap one to preview.
Built for the whole desk
A native app on every screen. The two-pane layout opens up beautifully on bigger displays.
iCloud sync
Your sheets sync automatically through iCloud — start a calculation on your iPhone and finish it on your Mac. No account to create, nothing to set up. They’re just there, everywhere.
.arithmos files — portable & future-proof
Share & collaborate
Work on a sheet with someone in real time — or send a polished copy in a tap.
Edit the same sheet together over SharePlay — every collaborator’s cursor in its own colour.
Turn any sheet into a clean, formatted PDF to send or print.
Open and edit .arithmos files in place, straight from the Files app.
In motion