Free Online Macro Calculator
Determine your daily macronutrient targets (protein, carbohydrates, and fats) using this accurate macro calculator. Easily convert between US Imperial units and UK/EU Metric units to calculate healthy nutrition goals based on guidelines from the CDC, NHS, and WHO.
How It Is Calculated
Calculating macronutrient targets starts with determining your body's energy requirements. First, your Basal Metabolic Rate (BMR) is calculated using the Mifflin-St Jeor formula, widely recognized as the most accurate standard formula for estimating metabolic rate:
Female: BMR = 10 * Weight (kg) + 6.25 * Height (cm) - 5 * Age (y) - 161
Next, your Total Daily Energy Expenditure (TDEE) is calculated by multiplying your BMR by your physical activity multiplier:
- Sedentary: TDEE = BMR * 1.200
- Lightly Active: TDEE = BMR * 1.375
- Moderately Active: TDEE = BMR * 1.550
- Very Active: TDEE = BMR * 1.725
- Extra Active: TDEE = BMR * 1.900
Your target calorie intake is then established according to your goals:
- Lose Weight: Target Calories = TDEE - 500 kcal
- Maintain Weight: Target Calories = TDEE
- Gain Muscle: Target Calories = TDEE + 300 kcal
Finally, the calorie target is divided into macronutrients based on the selected goal's split ratio. Protein and carbohydrates provide 4 kcal per gram, while fats provide 9 kcal per gram:
- Lose weight split (35% Protein, 35% Carbs, 30% Fat): Supports fat loss while retaining lean muscle.
- Maintain weight split (30% Protein, 40% Carbs, 30% Fat): A balanced ratio to support overall health and activity.
- Gain muscle split (30% Protein, 45% Carbs, 25% Fat): Higher carbohydrate availability to power strength training and muscle growth.
How to Use This Calculator
To make the most of your calculated macro split, follow these practical steps:
- Input Accuracy: Provide precise height and weight measurements. Be honest about your activity level; overestimating can lead to excessive calorie recommendations.
- Track Your Intake: Use a food logging app to record the meals you eat. Prioritize hit targets in order of priority: first hit your daily Calorie goal, second hit your Protein goal, and then let Carbs and Fats fill the remaining space.
- Monitor & Adjust: Evaluate your progress over 2 to 4 weeks. If weight loss or muscle gain is stalling, reassess your activity level or adjust your target calories slightly.
- Unit Conversion: Convert US Imperial units (pounds, feet, inches) to UK/EU Metric units (kilograms, centimeters) before inputting your data (e.g., weight in lbs divided by 2.20462 equals kg; height in inches multiplied by 2.54 equals cm) since the calculator's input forms are metric-based.
Reference Table: Typical Daily Macro Targets by Weight
This table shows average macro targets for individuals at various weights, assuming a moderate activity level (TDEE based on 1.55 activity multiplier) and a goal of maintenance.
| Body Weight | Target Calories | Protein (30%) | Carbohydrates (40%) | Fats (30%) |
|---|---|---|---|---|
| 60 kg | 1,900 kcal | 143 g | 190 g | 63 g |
| 70 kg | 2,100 kcal | 158 g | 210 g | 70 g |
| 80 kg | 2,300 kcal | 173 g | 230 g | 77 g |
| 90 kg | 2,500 kcal | 188 g | 250 g | 83 g |
| 100 kg | 2,700 kcal | 203 g | 270 g | 90 g |
Frequently Asked Questions
How accurate is this free online macro calculator?
This accurate macro calculator uses the Mifflin-St Jeor equation (the clinical standard endorsed by the Academy of Nutrition and Dietetics) to estimate your BMR, then applies activity multipliers to find your TDEE. While this calculation serves as an excellent scientific baseline, individual factors such as lean muscle mass, thyroid function, and genetics can influence your actual caloric needs.
What are the standard macronutrient distribution ranges?
According to the Acceptable Macronutrient Distribution Ranges (AMDR) established by the Food and Nutrition Board of the Institute of Medicine (referenced by the FDA and EFSA), healthy adults should aim for: - Carbohydrates: 45% to 65% of total daily calories. - Protein: 10% to 35% of total daily calories. - Fats: 20% to 35% of total daily calories. Our goals adjust these proportions within safe boundaries to optimize for fat loss, maintenance, or muscle gain.
How do I convert my weight and height from US Imperial to UK/EU Metric units?
To use this metric-based calculator with US Imperial measurements: - Divide your weight in pounds by 2.20462 to get kilograms (e.g., 150 lbs / 2.20462 ≈ 68 kg). - Convert your height to total inches (1 foot = 12 inches) and multiply by 2.54 to get centimeters (e.g., 5'8" is 68 inches; 68 * 2.54 = 172.7 cm).
Should macro ratios be adjusted for weight loss vs. muscle building?
Yes. For weight loss, health agencies like the NHS and CDC suggest a safe rate of 1 to 2 pounds (0.5 to 1 kg) per week. Increasing protein percentage (e.g., up to 35%) helps protect lean skeletal muscle during a calorie deficit. For muscle building, increasing carbohydrates (e.g., up to 45-50%) supplies the necessary glycogen to power heavy resistance training workouts.