Macro Calculator
Split your daily calories into protein, carbs and fat grams for your goal: enter your calories or estimate them from your age, height, weight and activity, pick a preset diet or your own split, and see grams per meal, fiber and limits.
How it works
grams = calories × share% ÷ (4 kcal/g protein & carbs, 9 kcal/g fat) · estimated calories = Mifflin-St Jeor BMR × activity factor ± goal (250, 500 or 1,000 kcal) · fiber = 14 g per 1,000 kcal · saturated fat and added sugar each under 10% of calories
Protein and carbohydrate carry about 4 calories per gram, fat about 9. Enter your daily calories, or let the calculator estimate them: it works out your basal metabolic rate with the Mifflin-St Jeor equation, multiplies by your activity level and adds or removes calories for your goal, never going below 1,200 kcal a day for women or 1,500 for men. Pick a preset split or enter your own percentages and the grams follow, divided across the number of meals you eat. The calculator also shows the fiber target from the Dietary Guidelines for Americans (14 g per 1,000 kcal) and the limits for saturated fat and added sugar (under 10% of calories each), and flags splits outside the US acceptable ranges (protein 10–35%, carbs 45–65%, fat 20–35%). Splits are conventions, not laws — total calories and protein adequacy matter most.
Worked example
On 2,200 kcal with the balanced 30/40/30 split: protein 2,200 × 30% ÷ 4 = 165 g, carbs 2,200 × 40% ÷ 4 = 220 g and fat 2,200 × 30% ÷ 9 = 73 g — over 4 meals about 41 g protein, 55 g carbs and 18 g fat each. Fiber target 31 g, saturated fat under 24 g and added sugar under 55 g a day. A 30-year-old man, 5′9″ and 170 lb, moderately active, who chooses "Estimate them for me" gets about 2,668 kcal to maintain, or 2,168 kcal for 1 lb a week of loss.
Sources: National Academies — Dietary Reference Intakes for energy and macronutrients (AMDR) · Dietary Guidelines for Americans 2020–2025 (fiber, saturated fat, added sugars) · Mifflin MD et al. (1990) — A new predictive equation for resting energy expenditure
Frequently asked questions
How much protein do I really need?
General guidance runs 0.7–1 g per pound of goal body weight for active people building or keeping muscle — often close to what the high-protein split yields. With "Estimate them for me" the calculator shows your protein per kg of body weight and warns if it is low.
Do macros matter more than calories?
Calories decide weight change; macros shape body composition, hunger and performance. Get calories right first, protein second, then split the rest by preference.
Is low-carb better for fat loss?
Controlled studies show similar fat loss at equal calories and protein. Choose the split you can stick to.
Can I set my own percentages?
Yes. Choose "Custom split" and enter protein, carbohydrate and fat shares that add up to 100%. The calculator flags any share outside the US acceptable ranges so you can check the plan is deliberate.
How many meals should I split my macros into?
Any number that suits you works for weight change. For muscle, 3–5 meals with 25–45 g of protein each is a practical pattern; set your number of meals and the per-meal table updates.
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This is a general educational estimate, not medical advice. Bodies differ — for decisions about diet, training, medication or health conditions, talk to a doctor or registered dietitian.