Keto Macro Calculator
This free keto macro calculator turns your body statistics into daily gram targets for the three macros that define a ketogenic diet: very low net carbs, adequate protein, and fat filling the rest. Choose a goal — fat loss, maintenance, or lean gain — and get calories plus a complete macro split you can start using today. Everything runs in your browser.
How the Calculation Works
First your daily energy is estimated: BMR via the Mifflin-St Jeor equation (or Katch-McArdle when you provide a body fat percentage), multiplied by your activity level, then adjusted for your goal — a 20% deficit for fat loss or a 5% surplus for lean gain. Net carbs are fixed at your chosen limit of 20, 25, or 30 grams, because staying under that ceiling is what makes the diet ketogenic. Protein is set from lean body mass at 1.4–2.0 g/kg depending on activity (or 1.6 g/kg body weight without a body-fat estimate) to protect muscle. Fat gets every remaining calorie — on keto, fat is the flexible lever you adjust for hunger, not a fixed quota.
Why Provide Body Fat Percentage?
With a body-fat estimate the calculator computes your lean body mass, switches to the Katch-McArdle BMR formula, and bases protein on the tissue that actually needs it. That usually means more accurate calories and a protein target that does not overshoot at higher body-fat levels. You can estimate body fat in two minutes with the Navy tape-measure method.
Typical Keto Macro Ratio
The output usually lands near the classic keto split: roughly 70–75% of calories from fat, 20–25% from protein, and about 5% from net carbs. The exact percentages differ by body size, activity, and goal — which is why calculating grams for your own numbers beats copying a generic ratio.