Macro & Nutrition Calculator

Precision macronutrient and dietary energy planning tool designed to optimize fat loss, athletic performance, and lean muscle hypertrophy.

Nutritional needs and metabolic rates vary based on individual health conditions, genetics, and lean muscle mass. This calculator provides evidence-based estimates for healthy adults. Consult a registered dietitian or physician before making drastic dietary changes.

How it works

Calculates baseline resting energy with the Mifflin-St Jeor formula, multiplies by your activity level, applies the appropriate caloric deficit or surplus for your goal, and breaks down the exact daily grams of protein, carbohydrates, and fats needed.

Formula

BMR = 10W + 6.25H - 5A + s, TDEE = BMR × Activity Factor, Target = TDEE ± Goal Offset, Protein = W × Goal Multiplier, Fat = (Target × 25%) / 9, Carbs = (Target - ProteinCals - FatCals) / 4

Computes your baseline resting calories (BMR) with the Mifflin-St Jeor equation, scales for workout frequency to get TDEE, offsets for your goal (-500 kcal for fat loss, +300 kcal for muscle gain), and divides the remaining calorie pool into optimal protein, healthy fat, and carbohydrate ratios.

Symbol	Variable	Unit
W	Body weight in kilograms	kg
H	Height in centimeters	cm
A	Age in full years	years
s	Sex constant (+5 for male, -161 for female)	kcal
Target	Target daily calorie expenditure	kcal

Worked example

70 kg male, 175 cm, 25 years old, moderately active, fat loss goal

Weight:: 70 kg
Height:: 175 cm
Age:: 25
Sex:: Male
Activity:: Moderately Active (1.55×)
Goal:: Fat Loss (-500 kcal)

BMR = 10×70 + 6.25×175 - 5×25 + 5 = 1,674 kcal. TDEE = 1,674 × 1.55 = 2,594 kcal. Target Calories = 2,594 - 500 = 2,094 kcal/day. Protein = 70 × 2.2 = 154g (616 kcal). Fat = (2,094 × 0.25) / 9 = 58g (524 kcal). Carbs = (2,094 - 616 - 524) / 4 = 239g (954 kcal). Water = 70 × 35 + 500 = 2.95 Liters.

Frequently asked questions

Why is protein higher during fat loss than maintenance?

When in a caloric deficit, your body is more prone to breaking down lean muscle tissue for fuel. Higher protein intake (2.2g per kg of body weight) protects existing muscle mass, boosts thermogenesis, and increases satiety.

How much of a calorie deficit is recommended for safe fat loss?

A 500 kcal daily deficit targets approximately 0.5 kg (1 lb) of fat loss per week, which is the gold standard for preserving lean mass and metabolic health.

What is the Devine formula for Ideal Body Weight (IBW)?

Developed in 1974 by Dr. Ben Devine, it calculates standard reference body weight based on height: 50.0 kg for men (45.5 kg for women) + 2.3 kg per inch over 5 feet.

BMR Calculator

Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation.

BMI Calculator

Calculate your Body Mass Index (BMI) from your height and weight, in kg/lb or cm/in.

Daily Water Intake & Hydration Calculator

Calculate your personalized daily hydration requirement in liters and standard glasses based on body weight and physical activity.

Running & Walking Pace Calculator

Calculate your running, jogging, or walking pace per kilometer and mile alongside average speed in km/h and mph.

Last reviewed: 2026-08-23.