Sigma
Notepad calculator for iPhone
Sigma has been on the App Store for 10 days. Here is what the data looks like. Downloads: 15 first-time installs
Impressions: ~2,000 (App Store search + browse)
Product page views: 58
Revenue: $25
In-app purchases: 4
Day 1 download-to-paid: 11.1%
Day 7 download-to-paid: 15.4%
The conversion number is the one I keep coming back to. More than 1 in 7 people who downloaded the app paid for it within a week. That tells me the product is working for the people who find it. The problem is not the product, it is discovery.
1,960 impressions and 58 product page views means most people scrolling past it do not tap through. That is an ASO problem and a reach problem. What I am doing about it: started posting on TikTok this week with a different format (AI persona carousels showing the app doing one real thing per post). No data on whether it converts yet, too early. But the screen-recording format was not getting traction so the experiment is worth running.
If you have downloaded Sigma or are looking at it, I would genuinely like to know what brought you to it and whether the free tier was enough to show you the value. Reply here or email me at the address on getsigma.app.
App: getsigma.app
It's out.
Submitted Saturday, approved the same day, went live Tuesday evening. Sigma is a notepad calculator for iPhone: plain English math on every line, live results in a second column, everything stays editable.
What is in 1.0:
- Full parser: arithmetic, percentages, ~170 currencies, ~60 unit conversions, variables, aggregates, math functions, dates, hex.
- Editor with bold headers, blueprint grid backdrop, live results in a second column.
- Sheet browser with three free sheets, Pro for unlimited.
- Onboarding, settings as a modal page sheet, six themes (Auto free, five Pro).
- Calculation reference modal showing everything the parser supports, with search and sticky headers.
- iCloud sync (Pro). Export to PDF, Markdown, plain text (Pro).
- Accessibility pass for VoiceOver, Dynamic Type, Smart Invert, Reduce Motion.
- Bilingual from day one: English and French, app and calculation reference.
App Store: https://apps.apple.com/app/id6768903761?mt=8&ct=launch-ih
I am building Sigma, a notepad calculator for iPhone. Going for the App Store next week. First public update; I have been heads down a month.
The problem I kept hitting: I would tap out a stack of numbers on the iPhone calculator, get a result, screenshot it, and an hour later have no idea what 4218.50 was. Rent split? Trip total? Tax on something? The number is fine in the moment and useless ten minutes later because there is no context attached.
Sigma is a notepad where each line can be a calculation. You write words, you write math, the result shows up on the right. The words stay. Change an input, everything downstream updates.
Plain-English math: 20% tip on 84.50, rent + utilities, 120 EUR to USD. Variables that carry across lines, live currency rates, unit conversions, dates, percentages. Six themes, a built-in reference for everything the parser knows about, optional iCloud sync, export to PDF, Markdown, and plain text.
The pricing bet I am making:
Free tier is three saved sheets, full parser, no watermarks, no ads, no nag. Pro is $1.99/mo, $14.99/yr with a 7-day trial, or $29.99 lifetime. Auto-renews, cancel anytime in Settings.
Three sheets is the part I am most uncertain about. Generous enough that a non-paying user gets a real calculator, not a teaser. Tight enough that anyone using the app daily hits the limit. The analytics for "tried to create a fourth sheet" is the conversion proxy I will watch closest in the first two weeks. Could end up being too tight or way too loose; I will find out.
Next week: App Store listing, screenshots, submission. No public beta for 1.0; I am shipping straight to the store and leaning on crash reporting on the live build.
Waitlist: getsigma.app
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