Comparison

Sigma Notepad Calculator vs visualOS

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Sigma Notepad Calculator

Features
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$610 left this month, before rent went out, and you never typed a sum. Sigma is a notepad that does the math while you write: every line shows its answer, and the total stays in view above the keyboard. Know what’s left before you spend it. Write "pay = $2400", then your bills, "rent: $1200" and "food: $380", and "left = pay - total" shows $820. Rent goes up? Change one number and everything below follows. Split the bill at the table. Dinner for four, tip included, comes to $51.75 each before anyone reaches for a card. Then send the whole sheet to the group chat as one image, every line and the total included. Know what the trip costs before you book. Flights in dollars, the hotel in euros, the train in Swiss francs: one total, all in, in your own currency. Rates stay live and keep working offline. Never add up the same list twice. Tick what’s paid and the total shows what’s still to pay. Give each part of a list a heading and each part gets its own total. And all the everyday math around it. How many days until an invoice is due. Whether a 220 cm sofa fits an 8 ft wall. What you really saved at the sale. What a week of freelance work comes to. Percentages, units, dates and currencies, written the way you’d say them, with square roots, hex and trigonometry when you need them. Every line answers as you type. No formulas, no grid, and one rule to learn: a colon counts, an equals sign doesn’t. Free: three sheets and the full calculator. No ads, no time limit. Sigma Pro keeps every month: unlimited sheets, iCloud sync, export to PDF, Markdown and plain text, and five more themes. Billed yearly, monthly, or once for life. New subscribers get a 7-day free trial on the yearly plan. Your sheets stay on your iPhone, and iCloud sync uses your own private iCloud database, never our servers. Works in English and French. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://getsigma.app/privacy

About

visualOS

This app offers an infinite canvas for visual thinkers, organizing notes, folders, images, and to-do lists. It works entirely offline, saving your data as real files in a folder on your device, which can then sync via your cloud service.

Highlights
  • Infinite canvas for visual thinking
  • Offline access and real file saving
  • Syncs with your own cloud storage
  • Organize notes, images, and to-dos
  • Hierarchical boards within boards
  • Markdown file support
  • Freehand drawing and magnetic arrows
Features
Currently charting
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visualOS is an infinite canvas for people who think visually. It is an infinite canvas for notes, folders, images, to-do’s and sketches. It works fully offline and saves to real files in a folder on your device. YOUR DATA IS A FOLDER YOU CAN OPEN Connect any folder on your disk and visualOS mirrors your canvas into it — every folder on the canvas is a real folder, every document a Markdown file, every image an image. Put the folder in iCloud or Dropbox and it syncs through your cloud, not ours. If you ever leave, everything stays readable. Forever. OFFLINE ISN'T A MODE. IT'S THE ARCHITECTURE. On a flight, on the train, in a studio with no signal — visualOS doesn’t care. There is no server to reach, so there is no spinner, no sync wheel, no login wall. Your canvas opens instantly because everything is already here. BOARDS WITHIN BOARDS Any board can hold more boards. A project becomes a world: moodboards inside client boards inside your studio. Drag elements into a board to file them away; breadcrumbs keep you oriented; a double-tap takes you deeper. NO ACCOUNT. NO SUBSCRIPTION. Open it and work. There's nothing to sign up for, nothing to verify, nothing to cancel. Pay once and it's yours forever — one purchase unlocks every Apple device. FREE IN THE BROWSER BUT THE APP GOES FURTHER Try visualOS free in your browser at visualos.app. When you're ready for it everywhere, the app adds what a browser can't: true offline access on the train or a plane, native pan-and-zoom gestures, Apple Pencil drawing, and your boards saved as real files that sync across iPhone, iPad and Mac through your own iCloud. EVERYTHING ELSE • Notes & rich text • Long-form documents stored as plain Markdown • Interactive to-do lists on the canvas • Images & PDFs — drag, paste or drop them in • Freehand drawing • Magnetic arrows that snap and bend • Search every board at once • Groups, locking and a snap grid Your ideas. Your files. ABOUT US As creatives, we’ve always relied on visual canvas tools to organize our thoughts, plan projects, and make sense of ideas. But one thing kept bothering us: our files and knowledge were always tied to cloud-based services. We wanted the freedom to access everything offline, without worrying about losing our work or giving up our privacy. So why can’t our own files on our device be visualized in the same intuitive way? And that’s how the idea for visualOS was born: a visual representation of your internal folder structure — offline, private, and secure. Your data stays on your device, where it belongs. We’re Sarah and Gerald, a husband-and-wife team who have been living, loving, and building things together for more than 20 years. Creating visualOS has been a ton of fun and thanks to AI we were able to push it further than we initially imagined. Now we’d love to hear what you think. If visualOS helps you work a little more creatively or makes your files easier to navigate, we’d be grateful if you shared it with others.

Screenshots

Sigma Notepad Calculator4 screens
visualOS4 screens

Verdict

The call

The clearest difference is price: Sigma Notepad Calculator at Free against visualOS's $12.99. visualOS's advantage is in-app purchases (none vs 3) and update cadence (every 5 days vs fortnightly). On ads there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Sigma Notepad Calculator is free to download; visualOS costs $12.99 up front. Sigma Notepad Calculator sells 3 in-app purchases, starting at $1.99 per month. visualOS asks for nothing beyond the download.

UpkeepUpdate frequency

Sigma Notepad Calculator ships an update fortnightly, visualOS every 5 days. Both last shipped on October 25, 2026.

Scorecard6 real differences · 5 level
Sigma Notepad Calculator versus visualOS: the parameters behind the verdict, then further details
ParameterSigma Notepad CalculatorvisualOS
PriceFree — better$12.99
Rating—4.4 (5 ratings) — better
Positive reviews—80.0% of reviews
Number of ratings—5 — better
Update frequencyFortnightlyEvery 5 days — better
AdsNoNo
In-app purchasesYesNo — better
Monetization—Paid
Best chart rank—#96 — better
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS17.015.0 — better
Further details — not scored
Size16 MB21 MB
Age rating4+4+
DeveloperSoules Studio LtdDorweiler & Reimertz GbR

In-app purchases

3 purchases

Sigma Notepad Calculator

Subscriptions2
  • Monthly$1.991 Month
  • Annual7 Days trial$14.991 Year
One-time1
  • Lifetime$29.99
None

visualOS

No in-app purchases

Questions

Is Sigma Notepad Calculator free?
Sigma Notepad Calculator is free to download, with in-app purchases available.
Is visualOS free?
visualOS costs $12.99, with no in-app purchases.
Do Sigma Notepad Calculator or visualOS have ads?
Neither Sigma Notepad Calculator nor visualOS shows ads.
Which is updated more often, Sigma Notepad Calculator or visualOS?
Sigma Notepad Calculator ships an update fortnightly, and visualOS every 5 days. Most recently, Sigma Notepad Calculator was updated on October 25, 2026 and visualOS on October 25, 2026.

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