What this version shows you
This page starts with male settings and a sample man: 40 years old, 5 ft 10 in (178 cm), and 180 lb (82 kg). For him the calculator shows:
- Mifflin-St Jeor: about 1,733 calories a day
- Harris-Benedict (revised): about 1,808 calories a day
- Katch-McArdle: appears when you add your body fat %
The male formulas give a higher number than the female ones at the same size. With Mifflin-St Jeor, the gap is 166 calories a day.
When muscle changes the answer
Mifflin-St Jeor and Harris-Benedict only know your weight, height, and age. They can't tell if your weight is mostly muscle or mostly fat. Two men with the same stats get the same result, even if one lifts five days a week.
Katch-McArdle works differently. It uses only your lean body mass: 370 plus 21.6 times your lean mass in kg. Say our sample man has 15% body fat. His lean mass is about 153 lb (69 kg), and Katch-McArdle gives about 1,869 calories. That is more than the other two, because it gives him credit for his muscle.
If you are carrying more body fat, the reverse can happen, and Katch-McArdle may come in lower.
Getting more from your BMR
- Measure your body fat with our body fat calculator for men, then add it here.
- Use TDEE for meal planning. BMR leaves out movement. Our TDEE calculator adds your activity.
- Treat every result as a range. Watch your weight for 2 to 3 weeks and adjust your calories.
For the basics, read what BMR is, or go back to the main BMR calculator.