Notepad Calculator vs Cairn
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Notepad Calculator
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Notepad Calculator is a smart calculator disguised as a notepad. Instead of juggling a calculator app and a notes app, just write what you're thinking — every line is calculated instantly, right next to your words. Write math the way you think Type expressions in plain language and get answers on the same line: 500 + 200 * 3 → solved as you type, no equals button needed 10 km in miles, 5 feet 6 inches + 8 in today + 3 weeks, Jan 1 2025 to Mar 1 2025 tax = 15% then reuse price + tax anywhere below 8%, VAT, tip, subtotals and totals with #tag aggregation Every answer becomes a variable you can reference later, so multi-step calculations stay readable. Powerful, all offline A fast local engine handles a huge range of math with no internet, accounts, or AI required: Functions: sqrt, sin, cos, tan, log, ln, exp, abs, round, max, min, pow, and more Constants: pi, tau, phi, e Units & conversions: length, weight, volume, time, speed, temperature, electrical, and custom units Currency conversion with offline-cached exchange rates and a live "Update Rates" refresh Statistics, percentages, bases & bitwise (hex/binary/octal), trig in degrees or radians Chinese large-number support (万 / 亿) and spelled-out numbers (million, billion) Make it yours Definition Sheet — define global variables, your own units (1 box = 12 items), and custom functions (f(x) = x * 2) that apply to every document Organize work into folders, pin, archive, and search across all notes Headers (# Title), dividers (---), and tag totals keep long sheets tidy Tint the results column, align answers, and adjust line spacing to taste Export any sheet to Markdown or CSV Built for Mac Menubar Quick Calc — pop open an instant calculator from the status bar without leaving your work iCloud sync — your notes and calculations follow you to iPhone and iPad Native Mac storage, autosave, and a clean three-pane layout (sidebar · editor · live results) Smart autocomplete for units, currencies, functions, and variables 10 interface languages with live switching Whether you're estimating a project budget, converting recipes, planning a trip, or just splitting a bill, Notepad Calculator turns your notes into a living spreadsheet — without the spreadsheet.
Cairn
Track important upcoming dates and past anniversaries with a versatile countdown and count-up tool. It offers precise timing, customizable reminders, and various visual displays to keep you informed. Integrates seamlessly with your devices and data.
- Countdown and count-up for any event
- Minute and second precision timing
- Customizable repeat intervals
- Time zone support
- Visual progress tracking
- Milestone markers
- Home and Lock Screen widgets
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Cairn counts down to the days you're waiting for, and counts up from the days you don't want to forget. Give it a date. It answers in days — 124 days to go, or 1,024 days since. Everything else gets out of the way. COUNTDOWN AND COUNT-UP, ONE MODEL • Days to go for anything ahead: a holiday, a trip, an exam, a due date • Days since anything behind: an anniversary, a baby's birth, the day you quit • Turn on minute precision when the hour matters — "3 days 4 hours", with seconds only in the final hour • Repeat yearly, monthly, weekly, every N days, or by the lunar calendar • Every event carries its own time zone, so flying across the world never shifts the number • Count only working days when a countdown is about business days • A date calculator for the days between two dates, or a date N days away — save the answer as an event • Pick up dates from a screenshot, a photo or a bit of text, and start a new event already filled in SEE WHERE IT STANDS • A countdown bar reads like a battery gauge: solid is what's left, full to empty • A count-up grid fills one square at a time, a day at a time • Milestones at 100, 365, 520, 1,000 and 1,314 days, marked right on the track • Ring, milestone track or heat grid — pick one per event, or just keep the number • A year view lays out all twelve months at once, so you can see which one is crowded; a month view lays them out day by day • Yearly events show which anniversary it is, and the day a countdown reaches zero gets a small celebration REMINDERS THAT ARRIVE ON TIME • Several reminders per event: days, weeks or months ahead, at the hour you choose • A daily digest each morning for what's today and what's this week • Live Activity and Dynamic Island for the last 24 hours • Time-sensitive delivery for the dates that shouldn't wait behind a Focus EVERYWHERE YOU LOOK • Home Screen widgets in small, medium and large: one event, a list, or a chart • Lock Screen widgets — inline, circular and rectangular — each pointed at the event you choose • An Apple Watch app and complications: circular, rectangular, inline and corner • A Control Center control for a new countdown in one tap • Ask Siri how long until anything, or find an event right from Spotlight • Share an event with family or friends: change the date and it changes for them too YOURS, AND ONLY YOURS • No account. Nothing to sign up for. • Syncs across iPhone, iPad and Mac through your own iCloud, and mirrors to Apple Watch from your iPhone • Import dates from Calendar and birthdays from Contacts — read only, never written back • Export everything to a single JSON file and import it back whenever you like; local snapshots and Recently Deleted bring back what you removed by mistake • App Lock asks for Face ID, Touch ID or your passcode when you come back • Cover photos with automatic tinting, six muted themes, categories, pinning, archiving and a share card • English, Simplified and Traditional Chinese, Japanese, Korean, German, Spanish, Brazilian Portuguese, French, Italian, Arabic, Persian, Hebrew and Thai — dates and month names included Cairn is free to download and keep up to 3 events. A one-time in-app purchase unlocks unlimited events. Previous users keep full access permanently; restore with the same Apple Account. No subscription, no ads, no tracking. A cairn is the pile of stones a trail keeps stacking to mark the way — one for every stretch you have walked.
Screenshots
Verdict
The clearest difference is price: Cairn at Free against Notepad Calculator's $2.99. Cairn also leads on update cadence (weekly vs fortnightly). Notepad Calculator's advantage is in-app purchases (none vs 1) and iOS requirement (17.0 vs 26.0). On ads and device support 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
Cairn is free to download; Notepad Calculator costs $2.99 up front. Cairn sells 1 one-off in-app purchase. Notepad Calculator asks for nothing beyond the download.
Notepad Calculator ships an update fortnightly, Cairn weekly. Both last shipped on October 31, 2026.
| Parameter | Notepad Calculator | Cairn |
|---|---|---|
| Price | $2.99 | Free — better |
| Rating | — | 5.0 (1 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | — | 1 — better |
| Update frequency | Fortnightly | Weekly — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | — | Free |
| Devices | iPhone, iPad, Mac | iPhone, iPad, Apple Watch |
| Requires iOS | 17.0 — better | 26.0 |
| Further details — not scored | ||
| Size | 4 MB | 17 MB |
| Age rating | 4+ | 4+ |
| Developer | 方成 印 | 飞 吕 |
In-app purchases
Notepad Calculator
No in-app purchases
Cairn
- Lifetime Unlock$2.99







