Macronutrient calculator

Splits a daily calorie target into protein, fat and carbohydrates based on body weight and goal — in grams, calories and percentages.

Free · No registration or payment

Calculation method

Unit system

Quick calculation examples:

Estimated TDEE: 2633 kcal/day · Target: 2633 kcal/day (Weight maintenance)

Result (2633 kcal/day)

Protein: 120 g/day
Fat: 75 g/day
Carbohydrates: 370 g/day

Unit: g/day, period: one day. Method source: the ISSN protein position stand (2017) and AMDR ranges (IOM, 2005).

The result updates as you change the fields. Your data never leaves the browser.

Only upon clicking, current data is sent to generate the PDF and is not stored.

How it is calculated

Protein and fat are calculated from body weight rather than as a share of calories: these are physiological requirements that should not shift with intake. Protein follows the ISSN position stand (1.4–2.4 g/kg depending on goal). Fat is estimated from body weight using a practical range of 0.8–1.2 g/kg, and the resulting percentage of energy is compared with the AMDR reference range of 20–35%. Carbohydrates take the remaining calories: they fuel training and brain function.

Formula

Protein(g) = weight × goal factor; Fat(g) = weight × 0.8…1.2; Carbs(g) = (calories − protein × 4 − fat × 9) / 4

Limits of the method

Calculating from total body weight overestimates protein in marked obesity — lean body mass is the better basis there. The model does not cover meal distribution, fibre or individual carbohydrate tolerance.

Sources of the method

This calculation is for reference only and is not medical advice, a diagnosis or a prescription. If you have a medical condition, are pregnant, take medication or have any doubts, discuss the result with a physician or a qualified nutrition professional.

How to use the macronutrient calculator

Choose your calculation mode

Either enter your existing calorie target, or let NutriFit calculate your Total Daily Energy Expenditure (TDEE) based on your age, sex, height, weight, and activity.

Select your goal and body weight

Choose fat loss (20% deficit), weight maintenance, or muscle gain (15% surplus). Body weight can be entered in kilograms or pounds.

Get your personalized macro targets

Instantly view your recommended protein, fat, and carbohydrate intake in grams, calories, and percentage of total energy.

Macronutrient calculation examples

Weight maintenance

Example 1: Weight maintenance

Adult weighing 75 kg (165 lbs), target intake 2,300 kcal/day, goal: maintenance.

Protein: 120 g (480 kcal, 21%) · Fat: 75 g (675 kcal, 29%) · Carbs: 286 g (1,145 kcal, 50%)

Weight loss

Example 2: Weight loss (deficit)

Adult weighing 80 kg (176 lbs), target intake 2,000 kcal/day (20% deficit), goal: weight loss.

Protein: 160 g (640 kcal, 32%) · Fat: 64 g (576 kcal, 29%) · Carbs: 196 g (784 kcal, 39%)

Weight gain

Example 3: Muscle gain (surplus)

Active athlete weighing 70 kg (154 lbs), target intake 2,600 kcal/day (15% surplus), goal: muscle gain.

Protein: 147 g (588 kcal, 23%) · Fat: 70 g (630 kcal, 24%) · Carbs: 345 g (1,382 kcal, 53%)

What are macronutrients?

Macronutrients are the three primary nutritional classes that supply the body with energy and building blocks for tissue repair and metabolic health.

Protein (4 kcal/g)

Crucial for muscle repair, enzyme and neurotransmitter synthesis, immune health, and preserving lean body mass during fat loss.

Dietary Fat (9 kcal/g)

Essential for steroid hormone production (testosterone, estrogen), cellular membranes, brain health, and absorption of vitamins A, D, E, and K.

Carbohydrates (4 kcal/g)

The primary, most efficient energy substrate for high-intensity exercise, cognitive function, and muscle glycogen replenishment.

How your goal influences macronutrient ratios

Macros for weight loss (fat loss)

During a caloric deficit, muscle tissue is prone to breakdown. Protein is raised to 1.8–2.2 g/kg (0.82–1.0 g/lb) to preserve muscle mass and enhance satiety. Fat is kept at 0.8–1.0 g/kg for hormonal health, with remaining calories dedicated to carbohydrates for workout intensity.

Macros for weight maintenance

At caloric balance, protein of 1.4–1.8 g/kg (0.64–0.82 g/lb) fully satisfies cellular turnover and recovery. Fat is set to 0.8–1.2 g/kg, and carbohydrates provide the rest for stable daily energy and stamina.

Macros for muscle gain (hypertrophy)

Combined with progressive resistance training and a moderate surplus (+10–15%), protein is set to 1.8–2.4 g/kg (0.82–1.1 g/lb) to maximize muscle protein synthesis. Carbohydrates are prioritized to sustain high training volume and glycogen recovery.

Why calculate protein and fat from body weight instead of percentages?

Fixed percentage splits (such as 40/40/20 or 50/30/20) are physiologically flawed. Your physiological requirement for essential amino acids and fats is dictated by your actual body mass and muscle tissue, not your caloric intake. During a calorie deficit, fixed percentages underfeed protein right when your body needs it most. Calculating in grams per kilogram of body weight is the evidence-based ISSN standard.

How often should I recalculate my macros?

Recalculate your macros whenever your weight changes by 2–3 kg (5–7 lbs), when your training routine shifts, or when moving between fat loss, maintenance, and muscle gain phases.

Frequently asked questions about macros

What are macronutrients and how do they work?▼

Macronutrients are proteins, fats, and carbohydrates. Protein (4 kcal/g) repairs tissues and protects muscles; fats (9 kcal/g) are needed for hormone balance and nutrient absorption; carbohydrates (4 kcal/g) fuel athletic training and cognitive function.

How should I set macros for weight loss?▼

Create a moderate calorie deficit (~20% below TDEE), elevate protein to 1.8–2.2 g/kg to protect muscle tissue, maintain fat at 0.8–1.0 g/kg for hormone regulation, and allocate all remaining calories to carbohydrates.

Why does NutriFit calculate protein and fat from body weight rather than percentages?▼

Biological requirements for amino acids and essential lipids depend on your body weight, not total energy intake. Fixed percentages (e.g. 40/40/20) cause protein deficiency during cuts and unnecessary excess during bulks.

What is the AMDR guideline for dietary fat?▼

The Acceptable Macronutrient Distribution Range (AMDR) recommends that fat comprise 20% to 35% of total calories. NutriFit calculates fat using 0.8–1.2 g/kg and checks the resulting percentage against this health range.

How often should I recalculate my macros?▼

Recalculate whenever your body weight changes by 2–3 kg (5–7 lbs), when your physical activity levels change, or when you switch your fitness goal.

Daily calorie needs calculator (TDEE) →

Calculates basal metabolic rate and total daily energy expenditure, plus calorie targets for losing, maintaining and gaining weight.

Water intake calculator →

Calculates daily fluid needs from body weight with adjustments for physical activity and hot climate.

Body composition calculator →

Estimates body fat percentage from circumferences, calculates fat and lean mass and body mass index.

Other calculators

Nutrition and dietetics

What next

Formula breakdowns, biomarker reference ranges and nutrition articles with cited sources are in the NutriFit knowledge base.

Go to the knowledge base