Which of our three apps do you need?

We make all three, so we do not mind which one you install. Most people want BMI Calculator. Pick one of the two diaries instead if you want to watch a number change over weeks.

All three are free to install. BMI Calculator is the cheapest if you ever do buy, and the only one of the three with no subscription.

SimplestMost complete

The one this site is about

BMI Calculator

Listed on Google Play as BMI Calculator: TDEE, Body Fat

Simplest, 1 of 3 by how much the app does

It turns a few measurements into BMI, body fat, waist ratios and daily calories, naming the formula behind each one, so it is the one to pick when you want today's answer rather than a record you keep adding to.

Rating: 4.5 on Google Play

FreeEvery calculator, children on the growth curves, your history and export.

PremiumOptional, and everything above stays free.Cloud backup and sync across devicesNo ads

Get BMI Calculator

Free on Google Play. No account, and it works offline.

Weight Diary

Listed on Google Play as Weight Diary: BMI & Fat Tracker

In between, 2 of 3 by how much the app does

It keeps every weigh-in and charts it over time, which makes it the better fit if the scale is the number you actually care about and you are working toward a goal with a date on it.

Rating: 4.67 on Google Play

FreeWeight tracking with charts, a target and its date, progress photos and export.

PremiumOptional, and everything above stays free.Trend line and advanced statisticsCloud backup and sync across devicesNo ads

Get Weight Diary

Free on Google Play.

Body Diary

Listed on Google Play as Body Diary: Measurements & Photos

Most complete, 3 of 3 by how much the app does

It tracks tape measurements and progress photos next to your weight, and passes weight and body fat both ways through Health Connect, so it is the one to choose when the scale alone has stopped telling you enough.

Works with Health Connect

Rating: 4.59 on Google Play

FreeWeight and tape measurements, progress photos, a target and its date, and export.

PremiumOptional, and everything above stays free.Trend line and advanced statisticsMore than one personHome screen widgetsCloud backup and sync across devicesNo ads

Get Body Diary

Free on Google Play.

The difference is time, not features

BMI Calculator answers what am I today, across as many methods as your measurements allow. The two diaries answer what is changing, and the more you want to record, the further along that line you go.

Already have one of these?

Then adding another is worth it only if it answers a different question. They do not share data with each other, so the second app starts empty and stays separate. Plenty of people run a diary for the trend and this one for the occasional full check, which is the pairing that actually earns its place on a home screen.

Feature by feature

Every cell below was read off that app's own purchase screen on 25 September 2026. Free means free with nothing to buy. Paid means that app charges for it.

Features compared across BMI Calculator, Weight Diary and Body Diary
Feature	BMI Calculator	Weight Diary	Body Diary
BMI, with the WHO and Asian cut pointsThe cut points the WHO advises for South and East Asian populations are lower.	Free	Free	Free
Body fat estimateThree published methods here, picked by which measurements you have.	Free	Free	Free
Waist ratiosWaist to height, waist to hip, and Body Roundness Index (Thomas and colleagues, 2013). Where the weight sits, rather than how much of it there is.	Free	Not in this app	Free
Calories, BMR, TDEE and macros	Free	Free	Free
Every formula named on screen, with its paperThe reason this app exists. A number you cannot trace is just a number.	Free	Not in this app	Not in this app
Children on the WHO growth curvesAges 5 to 19 read against their own age and sex, never adult cut points.	Free	Not in this app	Not in this app
Past readings and a chart	Free	Free	Free
Trend line and advanced statisticsA predicted direction rather than a list of past entries.	Not in this app	Paid	Paid
A target and its date	Not in this app	Free	Free
Body measurementsWaist, hips, chest, arms, thighs, and inch loss over time.	Not in this app	Not in this app	Free
Progress photos behind a PINBody Diary adds front, back and side photos on the paid tier.	Not in this app	Free	Free
More than one person	Free	Free	Paid
Health ConnectWeight and body fat, read and written both ways. Body Diary only.	Not in this app	Not in this app	Free
Home screen widgets	Not in this app	Not in this app	Paid
Export your dataReading it back in from a spreadsheet is a paid feature in both diaries.	Free	Free	Free
Cloud backup and sync across devices	Paid	Paid	Paid
No ads	Paid	Paid	Paid
Works offline, no account needed	Free	Free	Free

The dollar signs in the header are relative, not prices: one sign is the cheapest of the three and three signs the dearest, because the real price changes by country and goes on sale. Google Play shows you the price in your own currency before you pay anything, and each app is useful before you pay it.

BMI Calculator: One purchase, no subscription. There is nothing to renew and nothing to expire.
Weight Diary: A lifetime purchase or a subscription, whichever you pick at the paywall.
Body Diary: A lifetime purchase or a subscription, whichever you pick at the paywall.

On installs: BMI Calculator 100,000+, Weight Diary 4.6 million, Body Diary 1.5 million. The two diaries show lifetime device counts from our own Play Console, while BMI Calculator shows the bracket Google Play displays publicly, which is all we publish for it. They are not quite the same kind of number, so read the diaries as precise and this one as at least that many.

Free, no purchase needed
Behind that app's purchase
Not in that app at all

Why any of it costs money

All three are useful before you pay anything. That is deliberate. The calculators, your readings, your history and the charts are free in every one of them, because most people need a number and a record of it and nothing more, and those people should not have to buy anything.

What costs money is what costs us money. Cloud backup runs on servers that send a bill every month. Sync has to keep working across two operating systems as they both change underneath it. Photos take storage. Removing ads removes the thing that pays for the free tier, so it has to be paid for another way. Those are the parts sitting behind a purchase, and that purchase is what lets one person keep five apps maintained rather than abandoned.

What people say

Real reviews from Google Play, quoted exactly as written. Each one links to itself on the listing so you can check it.

Very easy to navigate and use. The accuracy is far superior to any other BMR/TDEE calculators I've seen. Great job to the developers!

Saiyan Youthon Google Play

I'm a dietitian and this app is very helpful in making diet plans❤ it gives so accurate calculations.

Mehak Fatimaon Google Play

Other than BMI, it gives your ideal weight, your nutrition plan, and your calorie intake

Abhimanyu Dhimanon Google Play

We can calculate our exact total daily energy expenditure and make custom nutrition plans.and make a perfect diet plan.great app

Mohit patelon Google Play

What a cool body calculator. It is very simple in use and works perfectly well. Recommend.

Kari Strayon Google Play

Excellent BMI app with so many other informative tools

Sahith Pon Google Play

If BMI Calculator is the one

Free on Google Play, no account, and it works offline. One purchase removes the ads if they ever start to bother you, and there is nothing to renew.

Coming soon

Free, no account, and it works offline. 100,000+ downloads on Google Play.

This is not medical advice. Body Numbers is a calculator. It does not diagnose, treat or monitor any condition, and no number it produces should replace a conversation with a doctor or a dietitian. If a result worries you, or if you are pregnant, unwell, or under eighteen, speak to a health professional.