Count calories from a photo on iPhone: how accurate is it?

MealMate is an iPhone app that counts calories from a photo. You take a picture of your plate, and it lists each food it sees with an estimated weight, calories, carbs, protein and fat, then adds it to your daily log. It's for people who want a rough, honest picture of what they eat without typing every ingredient into a form, it needs iOS 26 or later, and it's free to download on the App Store.

I'm the developer, and this is how it works.

Why do people give up on calorie counting?

The arithmetic is easy. The logging is what wears people down. A homemade stir-fry is six or seven ingredients, each one weighed, searched for and picked from a list of near-identical database entries. Three meals a day of that starts to feel like a second job.

A photo trades some precision for far less effort. That's the whole bet.

How do you log a meal from a photo?

1. Tap the scan button in the middle of the tab bar and photograph your plate, or pick a photo from your library. The analysis starts on its own.
2. You get a list: each food with a name, an estimated weight in grams, calories, and carbs, protein and fat.
3. If the result looks off, run the analysis again or correct the portion.
4. Tap Add to Daily. The meal goes into whichever day you have open, so yesterday's dinner works too.

On iPhones with a LiDAR scanner (the Pro models), the camera also measures the distance to the plate and estimates its diameter, which goes along with the photo as a size reference. That arrived in version 2.1.6.

When a photo won't do, the + button on the Daily screen opens manual entry: search a food database, or type a name and calories, with weight and macros optional.

How accurate is it?

Any photo calorie counter is guessing two things: what the food is, and how much of it there is. The amount is the hard part, because one picture shows no depth and nothing under the top layer. And some calories are invisible: oil in the pan, butter in the mash, sugar in a sauce or a drink.

MealMate's estimates come from Google's Gemini model, which names the foods in the photo and estimates their portions and nutrition.

To correct an estimate, tap the grams on any item and type the real weight; calories and macros scale in proportion. Editing the weight, name or calories of a photo result is part of the optional subscription. Without it, swipe to delete the entry and add it by hand.

For packaged food, the label beats any photo. For the rest, weighing a portion now and then calibrates your eye.

So treat a photo estimate as a starting point. It shows the shape of a day and the trend over weeks, not numbers you can trust to within a few percent. If you count carbs to dose insulin or follow a diet for a medical condition, use the numbers your doctor or dietitian gives you.

How are the daily calorie and macro targets set?

On first launch the app asks for your sex, age, height, current and goal weight, goal, activity level, how fast you want to change, and a diet type. The calorie target is the Mifflin-St Jeor estimate of resting energy times an activity factor, from 1.2 (sedentary) to 1.725 (very active). To lose or gain weight it subtracts or adds 250, 500, 750 or 1,000 kcal a day, depending on the speed you picked, and it never goes below 1,200 kcal for women or 1,500 kcal for men.

Macros follow the diet type: balanced is 50% carbs, 20% protein and 30% fat, keto is 5/20/75, and there are low carb, high protein, low fat and vegetarian splits too. The Daily screen shows the calories left and grams of carbs, protein and fat against their targets. Weight goes in the Profile tab, in kilograms or pounds, as a chart against your goal weight.

Where do my food photos go?

To analyse a meal, the photo goes to MealMate's server, which passes it to Google's Gemini model and sends back the result, so photo logging needs an internet connection.

You need an account (email, Google or Apple), which stores your food log, profile and weight history. You can delete your account in Settings. The app also collects analytics and crash reports.

Who is it for, and who isn't it for?

It's for people who stopped logging because it took too long, and for anyone who mostly eats home-cooked or restaurant food, where there's no barcode anyway.

It's the wrong tool if you need exact numbers for a medical diet or a competition cut. There's no barcode scanner, so packaged food means typing labels in. It doesn't sync with Apple Health, and it's iPhone only. And if counting makes your relationship with food worse, skip it.

How to get started

1. Install MealMate from the App Store on an iPhone with iOS 26 or later.
2. Sign up with email, Google or Apple.
3. Answer the setup questions to get your calorie and macro targets.
4. Tap the scan button and photograph your next meal.
5. Check the foods and portions, then tap Add to Daily.

FAQ

Is there an app that counts calories from a photo?

Yes. Photo calorie counters use an AI model to identify the food in a picture and estimate the portion. MealMate is one: a free-to-download iPhone app that lists each food on the plate with estimated grams, calories, carbs, protein and fat, and adds it to a daily log.

How accurate are photo calorie counters?

They give estimates, not measurements. The biggest errors come from portion size, which is hard to judge from one picture, and from calories a camera can't see, such as cooking oil and sugar in sauces or drinks. They're useful for daily totals and trends, especially if you correct the portion when you know it.

How do I log calories by taking a picture of my food?

In MealMate, tap the scan button, photograph your plate or pick a photo from your library, check the foods and grams it found, and tap Add to Daily.

Does MealMate upload my food photos?

Yes, for the analysis: the photo goes to MealMate's server, which uses Google's Gemini model to identify the foods and estimate portions, so photo logging needs an internet connection.

Is MealMate free?

MealMate is free to download, and photo logging and manual entry work without paying. An optional subscription adds editing of photo results, the vitamin and mineral breakdown, and custom targets. On the US App Store it's listed at $2.99 a month or $17.99 a year as of November 2026.

What's the easiest way to track calories and macros?

The one you'll keep doing. Photo logging takes the least effort, weighing every ingredient is the most precise, and many people mix the two: photos for most meals, labels for packaged food. MealMate does both on iPhone.