BodyCalWhat this BMR calculator does
Your Basal Metabolic Rate (BMR)is the number of calories your body burns at complete rest. It's the foundation of every nutrition plan — the base number you build your calorie and macro targets on. This calculator estimates your BMR using three respected formulas and shows them side by side, so you can see how they compare instead of trusting a single black-box number.
The three formulas
- Mifflin–St Jeor: the modern standard, validated as the most accurate for the general population. This is your best default.
- Harris–Benedict (revised): an older but still widely used equation, handy for comparison and often cited by other tools.
- Katch–McArdle: based on lean body mass rather than total weight, so it can be more accurate for lean, muscular people — but it needs your body fat percentage. Enter it above to unlock this one.
From BMR to a real plan
BMR on its own isn't your calorie target — it's what you'd burn doing nothing all day. To get the calories you actually burn, multiply your BMR by an activity factor to reach your TDEE. From there, eat below it to lose weight or above it to gain, and split those calories with our macro calculator. Don't eat below your BMR to speed things up — a moderate deficit below your TDEE is safer and works better.