How Accurate Is Apple Watch Calorie Tracking? Here’s the Truth

Your Apple Watch gives you a neat number at the end of each day, showing how many calories you’ve burned. But how accurate is that number, really? If you’re counting calories to lose weight, stay healthy, or hit fitness goals, accuracy matters. With real data and studies now available, let’s break it down.

Apple Watch Gets a Lot Right—But Calorie Estimates? Not So Simple

Apple Watch is incredibly reliable when it comes to heart rate and step tracking. Studies show it has a small error margin, just around 4.4% for heart rate and 8.1% for step count. That’s impressive for any wearable.

But when it comes to calorie tracking, the numbers can get murky. A major university meta-analysis revealed that Apple Watch has an average error rate of 28% for calorie estimates. Other tests show even bigger gaps, off by 18% to 40% depending on activity type. So if your Watch says you’ve burned 500 calories, it could actually be as low as 350 or as high as 600.

Why Apple Watch Calorie Estimates Vary So Much

Counting calories isn’t as straightforward as counting steps. To estimate your energy burn, Apple Watch combines:

• Your age, weight, height, and sex
• Whether you use a wheelchair
• Sensor data from heart rate, GPS, accelerometer, barometer, and motion
• Workout type and your stride length

Even with this tech stack, small factors can throw it off. Your metabolism, the fit of the watch, skin tone, and tattoos under the sensors can all impact accuracy. That’s not a flaw unique to Apple; it’s a challenge across the entire wearable industry.

Two Types of Calories: Active vs. Resting Energy

Your Apple Watch tracks two types of calories:

• Active Energy: Calories you burn by moving – walking, exercising, climbing stairs, etc.
• Resting Energy: Also called basal calories, this is the energy your body uses to stay alive – breathing, keeping your heart beating, and maintaining body temperature.

Your total daily energy burn is the sum of both.

How to Check Calories Burned on Apple Watch

The top red ring in the Fitness app shows the active energy you’ve burned. You can view this in the Activity app on your Apple Watch or in the Fitness app on your iPhone.

However, it doesn’t include resting energy. To see both active and resting energy:

1. Open the Health app on your iPhone
2. Tap on Show All Health Data
3. Look for the Active Energy and Resting Energy sections
4. Add the two together to get your total calories burned
5. You can also pin these to your Health app’s homepage for quick access. 
   

Also Read: How to Read Weekly Activity Summary on Apple Watch

How to Improve Apple Watch Calorie Tracking Accuracy

While you can’t make it perfect, you can reduce errors:

• Update your weight and height: Go to Health app > Browse > Body Measurements to make sure it’s accurate.
• Wear your Watch snugly: Loose watches reduce sensor accuracy, especially during workouts.
• Choose the correct workout type: The more precise the workout selection, the better the estimate.
• Enable Motion Calibration & Distance: Go to Settings > Privacy & Security > Location Services > System Services and turn this on.
• Calibrate your stride: A 20-minute outdoor walk or run helps your Apple Watch learn your movement patterns.
• Avoid tattoos under the sensor area: They can interfere with the sensors.
• Reset fitness calibration data if things seem off: Open the Watch app > Privacy > Reset Fitness Calibration Data.

So… Can You Trust Apple Watch Calorie Tracking?

Apple labels these numbers as estimates, and for good reason. If you’re an athlete or counting calories to the decimal, don’t rely solely on your Watch. But for most users looking to build habits, track progress, and close rings, the data is good enough.

Apple Watch may not be lab-accurate, but it excels at showing trends, boosting motivation, and keeping you on track.

Pro Tip: Use a Food Logging App

To get the full picture of calories in vs. out, pair your Apple Watch with apps like MyFitnessPal. Let your Watch handle activity tracking, and log your food manually. The combo gives you a much more balanced and actionable health view.

Related articles worth reading:

• Best Apple Watch health features to upgrade your wellbeing
• How to use Respiratory Rate on Apple Watch to measure your breathing rate
• How to set up and use fall detection on your Apple Watch