The numbers behind nutrition, explained
BMI, BMR, TDEE — three acronyms that decide how much you should eat, and most explanations of them are either hand-wavy or impenetrable. These guides give you the exact formulas, worked examples you can follow along with, and a straight answer on what each number is actually good for.
How to Calculate BMI
BMI = kg ÷ m²The body mass index formula in metric and imperial units, a full category chart, worked examples, and an honest look at where BMI falls short.
How to Calculate BMR
BMR = (10 × kg) + (6.25 × cm) − (5 × age) ± cMifflin-St Jeor, Harris-Benedict and Katch-McArdle compared, with step-by-step examples for men and women and guidance on which to use.
How to Calculate TDEE
TDEE = BMR × activity factorThe activity multiplier table, a full end-to-end example, and how to convert your total daily burn into a calorie target for any goal.
How the three numbers fit together
They answer different questions, and they build on each other in a specific order. Read them in sequence and the whole picture snaps into focus.
- 1
BMI — “Where am I now?”
Compares your weight to your height. A quick screening number — a starting reference, not a plan.
- 2
BMR — “What do I burn at rest?”
The calories your body needs just to stay alive. This is the foundation every calorie target is built on.
- 3
TDEE — “What do I burn in total?”
Your BMR multiplied by how much you move. This is your maintenance level — and the number you actually eat to.
Formulas give you a target. Hedgepal tracks it.
Snap a photo of any meal and get calories, protein, carbs and fats logged automatically — so the number you calculated has something real to measure against.