BMI Calculator vs WatchBMI
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
BMI Calculator
Calculate your Body Mass Index (BMI) using your weight and height to estimate body fat and assess health risks. This tool supports weight loss programs and offers metric and imperial system options.
- BMI calculation
- Weight tracking
- Metric and imperial system support
- Health risk assessment
- Weight loss program aid
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BMI Calculator helps you to calculate your Body Mass Index (BMI) based on body weight, height. The BMI is an estimate of body fat and a good gauge of your risk for diseases that can occur with more body fat. The higher your BMI, the higher your risk for certain diseases such as heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems, and certain cancers. Ideal to help you with your loss weight program, keeping track of you current weight. • This app supports metric and imperial system. Note: This app is just for reference all the calculation are made using the WHO body max index formula, all the information displayed in the app such as graphs are just representations of the values of the formula. Please consult your health provider if you think your health is on risk. WHO website where you can consult more information about body mass index. https://www.who.int/europe/news-room/fact-sheets/item/a-healthy-lifestyle---who-recommendations
WatchBMI
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This app is a BMI (Body Mass Index) calculator. It is very simple, in that it asks for input of height and weight, and displays the calculated value for BMI. It does not measure anything; it only displays the calculated BMI based on entered values. I created this for my own practice, because I often need to calculate BMI, and do not want to have to take out and unlock my phone every time. While it will certainly work for an individual to determine her own BMI, it is targeted at users (such as myself) who need to calculate BMI based on the measurements of multiple individuals. It does report the CDC category of the BMI, but does not otherwise interpret any of the data. It does not store or collect any of the entered information. You should know that BMI is only a reflection of height and weight; it does not assess body composition, or differentiate between fat and muscle. Instructions: Simply click on one of the buttons on the main screen to show a keyboard for entering the value. WatchBMI can accept values in either the Metric or the Imperial system. Click the "M" button to change to metric, click the "I" button to change to imperial If Imperial: Click on "Pounds" to enter the weight in pounds. Use the "Back" button to go back to the main screen. Click on "Feet" to enter the feet part of height. Click on "Inches" to enter the inches part of height. If Metric: Click on "Kilos:" to enter the weight in kilograms. Click on "Cms: to enter the height in centimeters. The app does not allow inches greater than 11, feet greater than 7, or weight greater than 999, with similar maximums in metric. Once all three values have been entered, the main screen (again, click the "Back" button) to show the calculated BMI and the CDC category for that BMI. When changing from Imperial to Metric or Metric to Imperial, the height and weight will change as well, so you can enter weight in kilograms and height in feet and inches. Reference Information: Information from the U.S. Centers for Disease Control and Prevention (CDC) provides information about BMI and its appropriate use at https://cdc.gov/bmi BMI is a measure of weight relative to height. According to CDC at https://www.cdc.gov/bmi/about/index.html : BMI is a quick, low-cost, and reliable screening measure for underweight, overweight, or obesity; BMI is a valuable population health measure used worldwide; for individuals, BMI should be considered with other factors, such as blood pressure, cholesterol levels, and physical examination. The CDC Adult BMI Categories are from https://www.cdc.gov/bmi/adult-calculator/bmi-categories.html. BMI and this app does not diagnose or treat any condition. The CDC BMI Categories calculated by this app are designed for adults 20 and older, and do not apply to children. Check with your doctor before using this app or making any medical decisions based on BMI.
Screenshots
Verdict
The clearest difference is price: BMI Calculator at Free against WatchBMI's $0.99. WatchBMI's advantage is ads (none vs shown) and update cadence (daily vs every 11 days). On 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
BMI Calculator is free to download; WatchBMI costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.
BMI Calculator ships an update every 11 days, WatchBMI daily. The most recent releases landed on October 13, 2026 and October 27, 2026 respectively.
| Parameter | BMI Calculator | WatchBMI |
|---|---|---|
| Price | Free — better | $0.99 |
| Rating | 4.0 (2 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 2 — better | — |
| Update frequency | Every 11 days | Daily — better |
| Ads | Yes | No — better |
| In-app purchases | No | No |
| Monetization | Ad-supported | — |
| Devices | iPhone, iPad, iPod | iPhone, iPod, Apple Watch |
| Requires iOS | 12.0 — better | 13.0 |
| Further details — not scored | ||
| Size | 31 MB | 0 MB |
| Age rating | 4+ | 17+ |
| Developer | Bosusoft | James Nachbar |
In-app purchases
BMI Calculator
No in-app purchases
WatchBMI
No in-app purchases
Questions
Is BMI Calculator free?
Is WatchBMI free?
Do BMI Calculator or WatchBMI have ads?
Which is updated more often, BMI Calculator or WatchBMI?
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