Hertz in CM vs Firstnum
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Hertz in CM
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This is a kind of unique dual calculator that gives you the distance (wavelength) in CM (centimeters) according to the selected frequency in Hertz or vice versa. All in relation to the property of the medium (CM/SEC). 34300 is chosen as an average speed of sound in air. 148100 is a good suggestion in water. It might be 'useful' for some people to have a stand-alone app for doing just this. To see more apps like this, go to www.discobajas.com
Firstnum
This utility app is designed for managing device access and logins. It helps users securely log in to control their devices.
- Device login management
- Secure access control
- User authentication
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Used for logging in to manage the device
Screenshots
Verdict
The clearest difference is price: Firstnum at Free against Hertz in CM's $0.49. Firstnum also leads on update cadence (every 5 weeks vs every 8 months). On ads, in-app purchases, device support and iOS requirement 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
Firstnum is free to download; Hertz in CM costs $0.49 up front. Neither carries in-app purchases, so what you see is what you pay.
Hertz in CM ships an update every 8 months, Firstnum every 5 weeks. The most recent releases landed on November 4, 2026 and November 5, 2026 respectively.
| Parameter | Hertz in CM | Firstnum |
|---|---|---|
| Price | $0.49 | Free — better |
| Rating | — | 3.0 (2 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | — | 2 — better |
| Update frequency | Every 8 months | Every 5 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | — | Free |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 13.0 | 13 |
| Further details — not scored | ||
| Size | 0 MB | 88 MB |
| Age rating | 4+ | 17+ |
| Developer | Stein Erik Nilsen | ShangHai Stoneoim Intelligent Technology Co.,Ltd |
In-app purchases
Hertz in CM
No in-app purchases
Firstnum
No in-app purchases
