The Lean calculators. Your expenditure and your needs, computed from measurements. Zero checkboxes.
Seven free calculators with transparent, sourced formulas, built on a single principle: you are never asked to guess your « activity level » in a menu. Your body is measured: body fat, steps, macros. Every tool starts there.
By The Lean Team · updated August 26, 2026
In which order to use them
The logic in one sentence
First measure your composition (body fat → lean mass), derive your expenditure (BMR → NEAT → TDEE), set your goal (deficit), feed it (protein), and watch your body's counterattack (metabolic adaptation). Each calculator feeds the next: the cards follow this order.
Body fat calculator
Your body fat percentage with a tape measure (validated US Navy method), your lean mass and your real BMR. The measurement that unlocks everything else.
Basal metabolic rate calculator
Your BMR on your lean mass, not a weight-based population formula. The foundation of your calorie budget.
NEAT calculator
How much your steps really burn, adjusted to your weight and stride. The most variable brick of your expenditure, finally quantified.
Full TDEE calculator
Your total expenditure, brick by brick: BMR + NEAT + EAT + TEF, on your real body fat. The number that steers everything.
Calorie deficit calculator
Your kcal target to cut without breaking your metabolism: reasonable deficit, loss projection, guardrails.
Protein calculator
Your grams per day on your lean mass by goal, split per meal, with concrete equivalents.
Metabolic adaptation calculator
Has your metabolism slowed during your diet, and by how much? The 100 to 0% coefficient your plateau calls for.
The theory behind the tools
Each calculator applies the full expenditure breakdown: TDEE = BMR + NEAT + EAT + TEF, with metabolic adaptation as the 5th brick modulating BMR (100→0 % convention). To understand each brick: the guide total daily energy expenditure, the pillar Basal Metabolic Rate (BMR)., and our study on calorie database reliability (857,655 products analyzed).
And if you would rather have all of this measured automatically: that is exactly what the app does. BodyScan AI for body fat, native pedometer for NEAT, macros counted with every logged meal, adaptation tracked continuously.
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