Propeller Calc vs AlcoCHECK
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Propeller Calc
This utility calculates propeller performance metrics like pitch, gear ratio, RPM, slip, and speed. Input any four values, and the app computes the fifth, helping users understand the relationship between propeller design and boat performance.
- Calculate pitch, gear ratio, RPM, slip, and speed
- Enter any four variables to find the fifth
- Understand propeller slip and its impact
- Supports iPhone and iPad
- Free to use
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This calculator can determine pitch, gear ratio, RPM, propeller slip and speed parameters. Enter any four variables, and it will calculate the fifth. Use the toggle switch to choose which field to calculate. Pitch is the theoretical forward movement for one complete turn of the propeller. Every inch of the boat in contact with the water induces drag. Therefore, the distance travelled differs since the propeller is "slipping" behind the theoretical distance it should travel with each rotation. The difference between theory and reality is called slip. Depending on your application, slip typically ranges between 5% and 20%. A lower number is only sometimes what you are after. Slip of a prop changes with operating conditions and is not a direct measure of efficiency. Please consult professionals for guidance. Happy powerboating
AlcoCHECK
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AlcoCHECK is the APP mainly for alcohol breath checker. Paired with alcohol tester, the APP will help users to store the testing results, and export the testing data. Meanwhile, users could choose take photoes or not when doing the alcohol checking. It is very helpful when users need records storage.
Screenshots
Verdict
The clearest difference is update cadence: AlcoCHECK at every 5 months against Propeller Calc's every 21 months. AlcoCHECK also leads on iOS requirement (12.0 vs 17.0). On price, ads, in-app purchases 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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Propeller Calc ships an update every 21 months, AlcoCHECK every 5 months. The most recent releases landed on September 26, 2026 and October 27, 2026 respectively.
| Parameter | Propeller Calc | AlcoCHECK |
|---|---|---|
| Price | Free | Free |
| Rating | 3.0 (1 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 21 months | Every 5 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad | iPhone, iPod |
| Requires iOS | 17.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 3 MB | 64 MB |
| Age rating | 4+ | 12+ |
| Developer | Frode Rørvik | Henan Hanwei Electronics Co., Ltd. |
In-app purchases
Propeller Calc
No in-app purchases
AlcoCHECK
No in-app purchases
Questions
Is Propeller Calc free?
Is AlcoCHECK free?
Do Propeller Calc or AlcoCHECK have ads?
Which is updated more often, Propeller Calc or AlcoCHECK?
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