Free Macro Calculator
A free macro calculator estimates how many grams of protein, carbohydrates, and fat you should eat each day based on your weight, height, goal, and target weight. kkal.ai uses the Mifflin–St Jeor equation, the formula registered dietitians most often recommend for healthy adults.
Last updated: May 2026 · Reviewed against the Mifflin–St Jeor equation (J Am Diet Assoc, 2005).
How we calculate your macros
- BMR: (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 (male) or − 161 (female).
- Activity factor: 1.2–1.9 depending on weekly training volume.
- Goal adjustment: −10–20% for weight loss, +250–500 kcal for gain.
- Macro split: 40/40/20 (P/C/F) for loss; 30/45/25 for maintenance or gain.
Frequently asked questions
What is a macro calculator?
A tool that estimates daily protein, carbohydrate, and fat targets in grams from your weight, height, age, sex, activity level, and goal.
How accurate is the Mifflin–St Jeor equation?
A 2005 J Am Diet Assoc review found it predicted resting metabolic rate within 10% of measured values in roughly 82% of non-obese adults — the highest accuracy among common predictive equations.
What macro split should I use for weight loss?
kkal.ai uses 40% protein, 40% carbs, 20% fat for loss — higher protein preserves lean muscle in a deficit and improves satiety.
Is the kkal.ai macro calculator free?
Yes. The macro calculator, BMR calculator, and AI meal photo analyzer are free on the web with no signup required.