Discover the Most Accurate AI Photo Calorie Tracker

I compared four popular calorie tracking apps: MacroFactor, Cal AI, MyNetDiary, and Snap Calorie. My goal was to assess their meal-photo logging accuracy across simple, medium, and complex meals.

Brief Overview of the 4 Apps

MacroFactor Overview

MacroFactor is a nutrition logger with built-in coaching capabilities. It was launched in 2021 by Greg and Lindsey Nuckols, Jeff Nippard, Cory Davis, and Rebecca Kekelishvili. The app is best known for its sophisticated algorithm that learns from user data to adjust nutritional targets based on progress (mainly weight trend) and preferences.

The coaching aspect can be customized or turned off completely for people who prefer to decide for themselves and only need a solid logging tool. 

A major 2025 update added photo-based meal logging alongside the already existing barcode and label scanning. In addition, users can log foods through the rich, highly accurate food library, or simply describe their meal and let the app do its magic. 

The downsides include MacroFactor not having a free version (only a 7-day trial, which you can extend to 2 weeks with code FEASTGOOD) and no recipe database beyond the personal recipes you can save.

Cal AI Overview

Cal AI is a calorie tracker built around one simple idea: log meals effortlessly. The main way to do so is through the app’s photo logging that includes an instant nutritional breakdown. 

MyFitnessPal acquired Cal AI in late 2025 in a deal that was rumored to be over $100 million, though that wasn’t confirmed by either side. Thanks to that deal, Cal AI users now have full access to MFP’s huge food library with millions of entries and options from 300+ restaurant chains. 

Cal AI has a clean interface, simple onboarding, a cool calorie rollover feature (which isn’t available on most apps), and streaks and badges that make for a gamified experience. 

During our testing, we noted that the app doesn’t have the nutritional target estimates and completely lacks automatic calorie and macro adjustments (something that MacroFactor does quite well), and its food library isn’t as controlled as some competitors. But today we’re testing its main selling feature: the photo meal logging, so read on to see how the app does.

MyNetDiary Overview

MyNetDiary Premium is the app’s paid tier. This calorie and macro tracker is built mainly around weight loss, though it can also support weight gain goals. The app leans into ease of use, visual feedback, and guided insights, which makes it a good option for beginners with no tracking experience. 

That said, MyNetDiary also works for more experienced users and athletes, thanks to its extensive, verified food database (2+ million entries) built on USDA and NCC sources. It tracks up to 108 nutrients per meal entry, more than any other app. 

The Advanced AutoPilot feature automatically adjusts targets based on a person’s metabolism, similar to MacroFactor’s algorithm. Premium also adds calorie and macro cycling, trend analysis, dashboard customization, and the ability to set up custom trackers. 

However, unlike the previous two apps discussed, even the free tier is generous: users can still track all 108 nutrients, use the barcode scanner, log meals via voice input, create a shopping list, and enjoy it all ad-free and offline.

Snap Calorie Overview

Snap Calorie is a photo-based meal logger with some AI functionalities. It was released in 2021, and its photo meal logging was launched in mid-2023. The company claims a mean caloric error of around 15% for photo-logged meals. 

The technology behind the app comes from research from Google Research and Perception Labs, including the Nutrition5k project published at CVPR 2021. Nutrition5k has 5,000+ weighted food plates and was used to evaluate various tools for their ability to estimate calories and macros.

Aside from photo meal logging, Snap Calorie offers voice logging, a barcode scanner, and a nutrition label scanner. The company claims to have 500,000+ foods, verified against USDA sources.

Overall, despite its rough early days (some of which we discussed in a 2023 review), this app is an interesting lower-profile alternative to Cal AI, particularly for users who value the research behind an AI food-estimation system

Test Rules to Keep Things Fair and Honest

• I prepared 3 meals: a simple one, a slightly more complex one, and a hard one.

• I knew the nutritional data for each meal before using the photo logging feature.

• I gave as little input as possible to each app to standardize the test.

Test Results

The following results are from opening each app, selecting the photo-logging feature, and taking a photo of each dish. I then compared each app’s estimation to the actual nutritional value of the meals.

I didn’t give any hints or directions to any of the apps during testing. This was my attempt at keeping things as fair as possible.

Easy Meal – Oven Baked Hoki Fish Fillet

To start, I wanted to give each app something super simple to tackle: a few fish fillets on a dish. The fish in question was hoki (a popular type of whitefish), known for its low-calorie and high-protein content. 

I weighed 217 grams of the fish (7.6 ounces), which had the following nutritional value: 167 calories, 33 grams of protein, 2 grams of carbs, and 3 grams of fat.

Let’s see the results:

• MacroFactor – 254 calories, 27.1 grams of protein, 3.8 grams of carbs, and 14.1 grams of fat.

• Cal AI – 105 calories, 22 grams of protein, 0 grams of carbs, and 1 gram of fat.

• MyNetDiary – 202 calories, 37 grams of protein, 0 grams of carbs, and 4 grams of fat.

• Snap Calorie – 206 calories, 22 grams of protein, 0 grams of carbs, and 12 grams of fat.

Meal	Calories	Protein	Carbs	Fats
Oven Baked Hoki Fish Fillet	167	33 grams	2 grams	3 grams
MacroFactor	254	27.1 grams	3.8 grams	14.1 grams
Cal AI	105	22 grams	0 grams	1 gram
MyNetDiary	202	37 grams	0 grams	4 grams
Snap Calorie	206	22 grams	0 grams	12 grams

Here, MyNetDiary came closest to the actual calorie value (though Snap Calorie was a close second). It also came within 4 grams of the protein content, and within 1-2 grams of the carbs and fat values.

Cal AI was a surprising outlier but in a bad way. It underestimated the overall nutritional value by more than 30%. MacroFactor overestimated the calories and fat content but came close on the protein and carbs.

Medium Hard Meal – Savory Quick Bread

The second meal was a slice of homemade savory quick bread that I made. I weighed all the ingredients, and the whole bread consisted of 6 servings, each 120 grams (4.2 ounces). A single serving had 336 calories, 22 grams of protein, 48 grams of carbs, and 6 grams of fat.

Let’s see how close each app came:

• MacroFactor – 329 calories, 12.8 grams of protein, 39.4 grams of carbs, and 12.7 grams of fat.

• Cal AI – 380 calories, 14 grams of protein, 25 grams of carbs, and 24 grams of fat.

• MyNetDiary – 501 calories, 16 grams of protein, 33 grams of carbs, and 34 grams of fat.

• Snap Calorie – 320 calories, 13 grams of protein, 40 grams of carbs, 11 grams of fat.

Meal	Calories	Protein	Carbs	Fats
Savory Quick Bread	336	22 grams	48 grams	6 grams
MacroFactor	329	12.8 grams	39.4 grams	12.7 grams
Cal AI	380	14 grams	25 grams	24 grams
MyNetDiary	501	16 grams	33 grams	34 grams
Snap Calorie	320	13 grams	40 grams	11 grams

Here, MacroFactor came closest overall, with its calorie estimate just 7 calories below the actual value and its carbs within 9 grams, although it significantly underestimated protein and overestimated fat.

Snap Calorie was a close second on calories and carbs, but also underestimated protein and overestimated fat.

MyNetDiary was the outlier, overestimating the meal by nearly 50% on calories and substantially overestimating fat. Cal AI also missed the mark considerably, particularly on carbs and fat.

Hard Meal – Mixed Salad

The final and hardest meal was a large salad served in a big bowl. It had cherry tomatoes, shredded cabbage and carrot, and cucumber, seasoned only with plain apple vinegar and salt. 

It was 490 grams with the following nutrition: 110 calories, 5 grams of protein, 20 grams of carbs, and 1 gram of fat. 

• MacroFactor – 193 calories, 2.7 grams of protein, 16.5 grams of carbs, and 14.2 grams of fat.

• Cal AI – 166 calories, 4 grams of protein, 18 grams of carbs, and 10 grams of fat.

• MyNetDiary – 63 calories, 3 grams of protein, 14 grams of carbs, and <1 gram of fat.

• Snap Calorie – 165 calories, 3 grams of protein, 12 grams of carbs, 12 grams of fat.

Meal	Calories	Protein	Carbs	Fats
Large Mixed Salad	110	5 grams	20 grams	1 gram
MacroFactor	193	2.7 grams	16.5 grams	14.2 grams
Cal AI	166	4 grams	18 grams	10 grams
MyNetDiary	63	3 grams	14 grams	<1 gram
Snap Calorie	165	3 grams	12 grams	12 grams

Here, MyNetDiary came closest overall, with the lowest calorie estimate and a very close carbs estimate, although it slightly underestimated protein. It was also the only app to accurately estimate the fats.

Cal AI and Snap Calorie were both fairly close on calories and carbs, but substantially overestimated the fat content. Lastly, MacroFactor was the biggest outlier, overestimating calories by 75% despite coming reasonably close on carbs and protein.

Overall Winner: It’s Complicated

If we take the above results at face value, MyNetDiary won, as it was closest to the true calorie value in two of the three tests and generally produced the most accurate macro estimates. MacroFactor performed best on the homemade bread, while Snap Calorie was also competitive across several of the meals. 

That said, these results shouldn’t be taken too seriously as a definitive test of accuracy. The point of photo meal logging isn’t necessarily to take a completely context-free photo and expect an app to perfectly determine the nutritional value. Rather, a photo gives a starting point, and providing additional context (such as the ingredients, portion size, or preparation method) can make the estimate far more useful.

There are too many variables that can change a meal’s nutritional value. Even something as simple as peanut butter can illustrate this: a flat spoonful might have 80 calories, while a slightly rounded spoonful could have 140+ calories. From a photo alone, an app can’t reliably know exactly how much was used. The same applies to the type of ingredients, their quantities, cooking methods, sauces, oils, and other factors.

What matters more is how well the app works as a whole. How intuitive is the interface? Is the food database validated? If so, what method was used? 

Despite winning in only one of the meals and overestimating the nutritional values in the other two, we lean toward MacroFactor being the overall best option. It actively asks for hints, allows you to easily replace foods and adjust quantities, and comes super close to the actual nutritional value of each meal with only a handful of modifications.