The notepad calculator iPhone never had.
Numi-style natural-language calc, built for iPhone
Do everyday math by just typing it out. Sigma reads plain English and answers as you go.
Name your numbers and reference them anywhere. No buttons, no modes. Just a notepad that calculates.
Now live on iPhone.
What it does.
Type it like a sentence.
Percentages, functions, and everyday phrasing. Sigma reads what you mean and answers in the margin, instantly.
Name once, reuse anywhere.
Declare a value, then reference it by name across the sheet. Change it once and everything downstream updates.
Convert as you type.
Live exchange rates and unit conversions, inline. Mix currencies in one sum and Sigma keeps the math straight.
Date math that just works.
Work out a deadline, a trip length, or the days until a date, without leaving the sheet.
Pricing.
Free
- Full calculator: arithmetic, percentages, units, currency, variables, aggregates, math functions, hex
- 3 saved sheets
- Auto theme
- English and French
No watermarks, no time limits, no ads.
Sigma Pro
- Everything in Free
- Unlimited sheets
- iCloud sync
- Export PDF, Markdown, plain text
- 5 additional themes
- Mono font picker
Common questions.
How is Sigma different from Numi?
Numi is the macOS reference for natural-language calculators and inspired Sigma's parser doctrine. Sigma brings the same idea to iPhone, where Numi does not ship.
| Sigma | Numi | |
|---|---|---|
| Platform | iPhone | macOS |
| Pricing | Free, Pro from $1.99 / month | Free, tip jar |
| Sync | iCloud (Pro) | None |
| Export | PDF, Markdown, plain text (Pro) | Plain text |
What's actually free?
Do my sheets sync between devices?
Which iOS versions are supported?
What happens if I cancel Pro?
Where is my data stored?
Sigma is on the App Store.
Free with three sheets and the full calculator. Sigma Pro unlocks unlimited sheets, iCloud sync, and export.