How your targets are calculated
The calculator first estimates your BMR — the calories your body burns at complete rest — using the Mifflin-St Jeor equation, the formula most dietitians consider the standard for the general population. Multiplying BMR by your activity level gives TDEE (total daily energy expenditure), and your goal shifts that number down for fat loss or up for muscle gain. The macro split then divides those calories using 4 calories per gram of protein and carbs, and 9 per gram of fat.
Protein is the anchor
Research consistently supports roughly 0.7–1 gram of protein per pound of body weight for people who train; the high-protein preset lands most users in that range. Protein preserves muscle in a deficit and drives recovery in a surplus, so if you customize anything, protect the protein number and let carbs and fat flex around it.
Expect to adjust after 2–3 weeks
Every formula carries a ±10% margin, because metabolism, daily movement, and even how much you fidget vary between people. Eat at your target for two to three weeks, weigh yourself under consistent conditions, and adjust by 100–200 calories if the scale trend doesn't match your goal. The number that works is the one your real-world results confirm.