Is it Prime? vs Kalc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Is it Prime?
Enter any number to instantly determine if it is a prime number or not. This straightforward utility provides a quick answer to your mathematical curiosity.
- Prime number identification
- Simple number input
- Instant yes/no results
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This application serves only one function - to satisfy your curiosity when you wonder whether a given number is prime or not. You put in the number, it says yes or no. Really, that's all it does.
Kalc
This utility app offers a unit converter, calculator, and world clock. Its user-friendly interface is designed for quick access to everyday calculations and conversions.
- Unit converter
- Calculator
- World clock
- Simple UI
- Quick results
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Unit Converter, Calculator, and World Clock. The simple & clean UI to get the results you need for everyday use as quickly as possible.
Screenshots
Verdict
The clearest difference is rating: Kalc at 4.7 against Is it Prime?'s 3.2. Kalc also leads on update cadence (every 9 days vs every 74 months) and review sentiment (96% vs 71%). On price, ratings volume, ads and in-app purchases 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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Kalc holds the better App Store score, 4.7 against 3.2. Both are backed by a comparable volume of ratings — 5 and 3 respectively. Written reviews point the same way: 71% of Is it Prime?'s written reviews are positive against 96% of Kalc's.
Is it Prime? ships an update every 74 months, Kalc every 9 days. Both last shipped on October 23, 2026.
| Parameter | Is it Prime? | Kalc |
|---|---|---|
| Price | Free | Free |
| Rating | 3.2 (5 ratings) | 4.7 (3 ratings) — better |
| Positive reviews | 71.4% of reviews | 96.2% of reviews — better |
| Number of ratings | 5 — better | 3 |
| Update frequency | Every 74 months | Every 9 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 15.0 | 13.4 — better |
| Further details — not scored | ||
| Size | 1 MB | 24 MB |
| Age rating | 4+ | 4+ |
| Developer | Wismar | YUTA OKAJIMA |
Customer experience
Is it Prime?
Kalc
In-app purchases
Is it Prime?
No in-app purchases
Kalc
No in-app purchases
