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Macro Calculator

Find your ideal daily protein, carbohydrate, and fat targets in grams based on your weight, height, age, sex, activity level, and whether you want to lose, maintain, or gain weight.

Biological sex
Enter your age, height, weight, activity level, and goal to see your daily macro targets.

Quick answer

A macro calculator uses the Mifflin-St Jeor formula to find your Basal Metabolic Rate (BMR), then multiplies it by an activity factor to get your Total Daily Energy Expenditure (TDEE). Calories are then distributed across protein (30%), carbohydrates (40%), and fat (30%) based on your goal — with a 500 kcal deficit for weight loss or a 300 kcal surplus for muscle gain. Protein and carbs each provide 4 kcal per gram; fat provides 9 kcal per gram. Most adults targeting weight loss need roughly 1,200–1,800 kcal/day, while those building muscle may need 2,500–3,500 kcal/day.

Formula & method

BMR (male) = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
  • weight — Body weight in kilograms
  • height — Height in centimetres
  • age — Age in years

Mifflin-St Jeor equation for men. Produces resting calorie burn in kcal/day.

BMR (female) = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
  • weight — Body weight in kilograms
  • height — Height in centimetres
  • age — Age in years

Mifflin-St Jeor equation for women.

TDEE = BMR × Activity Factor
  • BMR — Basal Metabolic Rate from Mifflin-St Jeor
  • Activity Factor — Multiplier based on exercise frequency (1.2 – 1.9)

Activity factors: Sedentary 1.2, Lightly active 1.375, Moderately active 1.55, Very active 1.725, Extremely active 1.9.

Protein (g) = (TDEE_goal × 0.30) ÷ 4 | Carbs (g) = (TDEE_goal × 0.40) ÷ 4 | Fat (g) = (TDEE_goal × 0.30) ÷ 9
  • TDEE_goal — Adjusted calorie target after applying the +300 gain or −500 loss offset

Standard balanced macro split: 30% protein, 40% carbs, 30% fat. Protein/carbs = 4 kcal/g; fat = 9 kcal/g.

Examples

Example 1: 30-Year-Old Male, Moderately Active — Maintain Weight
Input
Sex: Male | Age: 30 | Height: 180 cm | Weight: 80 kg | Activity: Moderately active | Goal: Maintain
Result
2,759 kcal/day — Protein: 207 g | Carbs: 276 g | Fat: 92 g
Why
BMR = 10×80 + 6.25×180 − 5×30 + 5 = 800 + 1,125 − 150 + 5 = 1,780 kcal. TDEE = 1,780 × 1.55 = 2,759 kcal. Protein = (2,759 × 0.30) ÷ 4 = 207 g; Carbs = (2,759 × 0.40) ÷ 4 = 276 g; Fat = (2,759 × 0.30) ÷ 9 = 92 g.
Example 2: 25-Year-Old Female, Lightly Active — Lose Weight
Input
Sex: Female | Age: 25 | Height: 165 cm | Weight: 60 kg | Activity: Lightly active | Goal: Lose weight
Result
1,350 kcal/day — Protein: 101 g | Carbs: 135 g | Fat: 45 g
Why
BMR = 10×60 + 6.25×165 − 5×25 − 161 = 600 + 1,031.25 − 125 − 161 = 1,345.25 kcal. TDEE = 1,345.25 × 1.375 = 1,850 kcal. Target = 1,850 − 500 = 1,350 kcal. Protein = (1,350 × 0.30) ÷ 4 = 101 g; Carbs = (1,350 × 0.40) ÷ 4 = 135 g; Fat = (1,350 × 0.30) ÷ 9 = 45 g.
Example 3: 40-Year-Old Male, Very Active — Gain Muscle
Input
Sex: Male | Age: 40 | Height: 175 cm | Weight: 90 kg | Activity: Very active | Goal: Gain muscle
Result
3,403 kcal/day — Protein: 255 g | Carbs: 340 g | Fat: 113 g
Why
BMR = 10×90 + 6.25×175 − 5×40 + 5 = 900 + 1,093.75 − 200 + 5 = 1,798.75 kcal. TDEE = 1,798.75 × 1.725 = 3,103 kcal. Target = 3,103 + 300 = 3,403 kcal. Protein = (3,403 × 0.30) ÷ 4 = 255 g; Carbs = (3,403 × 0.40) ÷ 4 = 340 g; Fat = (3,403 × 0.30) ÷ 9 = 113 g.
Example 4: 22-Year-Old Female, Moderately Active — Maintain Weight
Input
Sex: Female | Age: 22 | Height: 170 cm | Weight: 65 kg | Activity: Moderately active | Goal: Maintain
Result
2,234 kcal/day — Protein: 168 g | Carbs: 223 g | Fat: 74 g
Why
BMR = 10×65 + 6.25×170 − 5×22 − 161 = 650 + 1,062.5 − 110 − 161 = 1,441.5 kcal. TDEE = 1,441.5 × 1.55 = 2,234 kcal. Protein = (2,234 × 0.30) ÷ 4 = 168 g; Carbs = (2,234 × 0.40) ÷ 4 = 223 g; Fat = (2,234 × 0.30) ÷ 9 = 74 g.

Frequently asked questions

What is a macro calculator and how does it work?

A macro calculator estimates your daily protein, carbohydrate, and fat targets in grams. It first computes your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor formula, then multiplies by an activity factor to get your Total Daily Energy Expenditure (TDEE). That calorie target is then split by percentage across the three macronutrients based on your goal.

How accurate is the Mifflin-St Jeor formula?

The Mifflin-St Jeor equation is considered the most accurate predictive BMR formula for most adults, with an average error of about ±10% compared to indirect calorimetry. It was validated in a study of 498 subjects published in the American Journal of Clinical Nutrition. Individual results can vary with body composition, so athletes with high muscle mass may find their actual needs are slightly higher.

Why is fat 30% of calories even though it has more than twice the calories per gram of protein or carbs?

Dietary fat is calorie-dense (9 kcal/g versus 4 kcal/g for protein and carbs), so even a 30% calorie share translates to a relatively small gram amount. Dietary fat is essential for hormone production, fat-soluble vitamin absorption (A, D, E, K), and cell membrane integrity. Most nutrition guidelines recommend keeping fat between 20–35% of total calories.

Should I eat more protein to lose weight faster?

Higher protein intake (up to 35–40% of calories) during a caloric deficit helps preserve lean muscle mass, increases satiety, and has a higher thermic effect (about 20–30% of protein calories are burned during digestion). This calculator uses a standard 30% protein baseline; if you are actively resistance training during a cut, consider increasing protein to 35% and reducing carbs proportionally.

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — essentially the energy needed to keep your organs functioning. TDEE (Total Daily Energy Expenditure) adds your physical activity on top of BMR using a multiplier ranging from 1.2 (sedentary) to 1.9 (extremely active). You should eat at your TDEE to maintain weight, not at your BMR.

How do I track my macros?

Use a food diary app (MyFitnessPal, Cronometer, or Lose It) to log every meal and see the protein, carb, and fat breakdown in grams. Weigh foods with a kitchen scale for the first few weeks to build accurate portion intuition. Focus on hitting your protein target first — it is the most critical macro for body composition — then distribute remaining calories between carbs and fat based on preference and energy needs.

Sources & references

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Provided “as is” for general information only — results may be inaccurate, so verify before you rely on them. No warranty; use at your own risk.

Built and reviewed by HIFreeTools against the formula shown above and any authoritative references cited on this page. See our methodology and editorial standards.

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