How Accurate Are Exercise Calorie Calculators?
A calorie calculator estimates what an activity might burn using its intensity, your body weight, and how long you do it. It cannot measure your own calorie burn, and there is no single accuracy percentage we can promise for every person.
Why do two calculators give different answers?
They may count different things. For a 75 kg (165 lb) adult walking for 30 minutes at 3 mph (4.8 km/h), the same MET formula gives 110 net kcal above rest and 150 gross kcal including rest. Both figures come from the same formula. One includes resting energy and the other leaves it out.
Pace, hills, breaks, technique, body weight, and the chosen activity intensity also affect the answer. A watch or another app may make different assumptions.
What can change the result?
| What can vary | What to check |
|---|---|
| Food recipe | Generic USDA data may differ from a current brand or restaurant label. |
| Serving weight | A slice, bag, or cup can vary. Match the actual amount. |
| Activity intensity | Use the stated pace and terrain; exclude rest stops from active time. |
| Individual physiology | Standard METs do not measure your resting metabolic rate or efficiency. |
Why doesn’t the same MET value fit everyone?
The Compendium uses a standard reference of 3.5 mL of oxygen per kilogram per minute for 1 MET. Actual resting metabolism varies. Its explanation of corrected METs discusses why a standard reference does not fit every person.
Effort Eater uses standard MET values so you can check how each result was calculated. The choices are explained in the methodology. Showing more decimal places would not make the food or activity estimates more accurate.
Questions about accuracy
Should I use net or gross calories?
Use net when comparing activity energy above what you would use at rest. Use gross when asking about all energy during that period. Keep the basis consistent across activities.
Can these results predict weight loss?
No. The calculation compares energy amounts and does not model appetite, changes in food intake, metabolism, or long-term behavior.
Why do the results sometimes look so precise?
The formula can produce an exact-looking number even when its inputs are estimates. We round results to make them easier to read, but that does not make them personal measurements.
Last checked . Published by Effort Eater.
Sources and assumptions
Activity intensities come from the 2024 Adult Compendium. Walking uses 3.8 MET (code 17190), running 8.5 MET (12030), and cycling 6.8 MET (01020). The methodology and activity source links explain the formula, the pace for each activity, and the difference between energy above rest and total energy.
The times count active minutes and leave out breaks. Your own calorie burn may differ. These figures are not medical advice, a weight-loss prediction, or a reason to exercise to make up for eating.