Four methods. One page. Find your number and stop guessing.
Not all calorie formulas are created equal. The Quick Method is fast. Mifflin-St Jeor is the clinical standard. Harris-Benedict is the original. Katch-McArdle is the most accurate — if you know your body fat percentage. Use them all and compare.
The fastest way to estimate your maintenance calories. Multiply your bodyweight in pounds by 15. It's not the most precise tool in the box but it's accurate enough to get started and takes about three seconds.
To lose weight: subtract 300–500 kcal • To gain: add 300–500 kcal
02
Clinical standard
Mifflin-St Jeor
The most widely used formula in clinical nutrition settings. Developed in 1990, it accounts for age, height, weight, and sex to estimate your Basal Metabolic Rate (BMR) — the calories you burn at complete rest. Multiply by your activity level to get your Total Daily Energy Expenditure (TDEE).
BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5Then multiply by activity multiplier to get TDEE
lbs
ftin
yrs
Basal Metabolic Rate (BMR)
—
calories at rest
Total Daily Energy Expenditure (TDEE)
—
maintenance calories / day
To lose weight: subtract 300–500 kcal • To gain: add 300–500 kcal
03
The original formula
Harris-Benedict
The original BMR formula, developed in 1919 and revised in 1984. It uses the same inputs as Mifflin-St Jeor but with different coefficients. Generally produces slightly higher estimates. Useful to compare both and average the results for a more reliable target.
To lose weight: subtract 300–500 kcal • To gain: add 300–500 kcal
▲
Optional — feeds into Katch-McArdle
Body Fat Estimator
The Katch-McArdle formula requires your body fat percentage. If you don’t have it from a DEXA scan or calipers, use this Navy Method estimator. All you need is a tape measure. Measure at your waist (at the navel), neck (below the Adam’s apple), and your height. Takes 60 seconds.
Navy Method: uses waist, neck, and height circumferencesAccuracy: ± 3–4% — good enough for Katch
in
Measure at the navel
in
Below the Adam’s apple
ftin
Estimated Body Fat
—
% body fat (Navy Method estimate)
—
04
Most accurate — requires body fat %
Katch-McArdle
The most accurate BMR formula available — but only if you know your body fat percentage. Unlike the other formulas, Katch-McArdle calculates from lean body mass rather than total weight. This makes it especially valuable for men who carry significant muscle, where other formulas tend to overestimate calorie needs.
BMR = 370 + (21.6 × Lean Body Mass in kg)Lean Body Mass = Total Weight × (1 − Body Fat %)
⚠
This formula requires your body fat percentage.
If you don’t have it from a DEXA scan or body fat calipers, use the Navy Method estimator above to get an estimate. Without an accurate body fat percentage this formula will not give you reliable results — use Mifflin-St Jeor or Harris-Benedict instead.
lbs
%
Use estimator above or your DEXA result
Lean Body Mass
—
lbs of muscle, bone, and organ
Basal Metabolic Rate (BMR)
—
calories at rest
Total Daily Energy Expenditure (TDEE)
—
maintenance calories / day
To lose weight: subtract 300–500 kcal • To gain: add 300–500 kcal
Want the Full Nutrition System?
These calculators give you the number. The Long Game gives you everything you do with it — protocols, meal plans, recipes, the Klein Method, and the mindset to make it stick.