Macro Calculator — Free Online Macronutrient Calculator

How to Use the Macro Calculator

1. Select your unit system: Toggle between Metric (kg/cm) and Imperial (lbs/ft) at the top. The calculator adjusts all weight and height fields accordingly.
2. Enter your personal details: Input your age, biological sex, weight, and height. These values are used to calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, which forms the foundation of your calorie and macro estimates.
3. Choose your activity level: Select the option that best describes your typical weekly exercise routine from the dropdown. Options range from Sedentary (desk job, no exercise) to Very Active (intense training twice daily). Be conservative in your selection — most people overestimate their activity level.
4. Select your fitness goal: Choose Maintain Weight (balanced 30/40/30 split), Lose Weight (high protein 40/30/30 split), or Gain Weight (high carb 30/50/20 split). Each goal uses an evidence-based macro ratio optimized for that objective. The calorie target adjusts automatically: maintenance keeps TDEE, weight loss subtracts 500 calories, and weight gain adds 500 calories.
5. Review your results: The results panel displays your daily calorie target, a pie chart showing the proportion of each macronutrient, and cards showing the exact grams and calories for protein, carbohydrates, and fat. A macro bar at the bottom provides additional visual context. All values update instantly when you change any input.

The default values show results for a 30-year-old moderately active male maintaining weight. Replace these with your own data to get personalized macro targets.

Macro Calculation Formula and Method

Macronutrient targets are calculated by first determining your daily calorie needs, then splitting those calories into protein, carbs, and fat based on your selected goal.

Variables Explained

• Total Calories: Your daily calorie target based on TDEE adjusted for your goal. Maintenance = TDEE; weight loss = TDEE - 500; weight gain = TDEE + 500. Subject to minimum calorie floors (1,500 for males, 1,200 for females).
• Protein%: The percentage of total calories from protein. Protein provides 4 calories per gram. Higher protein intake preserves muscle during weight loss, enhances satiety, and supports muscle growth during bulking phases.
• Carbs%: The percentage of total calories from carbohydrates. Carbohydrates also provide 4 calories per gram. They are the body's preferred fuel source, especially during moderate to high intensity exercise, and are critical for brain function.
• Fat%: The percentage of total calories from fat. Fat provides 9 calories per gram, making it the most calorie-dense macronutrient. Essential for hormone production, nutrient absorption, and cell membrane structure.

Step-by-Step Calculation Example

Consider a 30-year-old moderately active male (75 kg, 175 cm) who wants to lose weight:

1. Calculate BMR: 10(75) + 6.25(175) - 5(30) + 5 = 1,699 cal/day
2. Calculate TDEE: 1,699 x 1.55 (moderate) = 2,633 cal/day
3. Weight loss calories: 2,633 - 500 = 2,133 cal/day
4. Apply weight loss ratio (40/30/30):
5. Protein: (2,133 x 0.40) / 4 = 213g protein (853 calories)
6. Carbs: (2,133 x 0.30) / 4 = 160g carbs (640 calories)
7. Fat: (2,133 x 0.30) / 9 = 71g fat (640 calories)

This person would aim for approximately 213 grams of protein, 160 grams of carbohydrates, and 71 grams of fat daily to lose about one pound per week while preserving lean muscle mass. The high protein percentage helps maintain satiety and muscle during the caloric deficit.

Practical Examples

Example 1: Mia Designs a Meal Plan for Fat Loss

Mia is a 29-year-old woman (63 kg, 168 cm) who exercises 4 days per week and wants to lose body fat while maintaining her strength training performance. Using the calculator with weight loss selected:

• TDEE (moderate, x1.55): 1,396 x 1.55 = 2,164 cal/day
• Weight loss target: 2,164 - 500 = 1,664 cal/day
• Protein (40%): 166g | Carbs (30%): 125g | Fat (30%): 55g

Mia builds her daily meals around these targets: a breakfast of Greek yogurt with berries and nuts (30g protein, 25g carbs, 15g fat), a lunch of grilled chicken salad with olive oil dressing (40g protein, 20g carbs, 15g fat), an afternoon protein shake with a banana (30g protein, 30g carbs, 2g fat), and a dinner of salmon with sweet potato and vegetables (40g protein, 35g carbs, 18g fat). Snacks fill the remaining macros. She tracks for three weeks and adjusts based on scale trends and energy levels.

Example 2: Andre Fuels a Muscle-Building Phase

Andre is a 26-year-old man (80 kg, 182 cm) who lifts weights 5 days per week and wants to gain lean muscle. Using the calculator with weight gain selected:

• TDEE (active, x1.725): 1,793 x 1.725 = 3,093 cal/day
• Weight gain target: 3,093 + 500 = 3,593 cal/day
• Protein (30%): 270g | Carbs (50%): 449g | Fat (20%): 80g

Andre structures his eating around his training schedule. He consumes 50g of carbs and 30g of protein before workouts and a similar post-workout meal to maximize muscle protein synthesis and glycogen replenishment. He hits his high carb target through rice, oats, whole-grain bread, pasta, fruits, and starchy vegetables. His protein comes from chicken, fish, eggs, dairy, and one whey protein shake daily. He monitors his waist measurement alongside scale weight to ensure most of his weight gain is muscle rather than fat.

Example 3: Rachel Maintains Her Goal Weight

Rachel is a 40-year-old woman (60 kg, 165 cm) who recently reached her goal weight after a 6-month diet. She does yoga 3 times per week and walks daily (lightly active). She wants to find her maintenance macros to avoid regaining weight:

• TDEE (light, x1.375): 1,302 x 1.375 = 1,790 cal/day
• Maintenance ratio (30/40/30):
• Protein (30%): 134g | Carbs (40%): 179g | Fat (30%): 60g

Rachel uses these macros as a flexible framework rather than rigid targets. She prioritizes hitting her protein target of 134g daily to prevent muscle loss as she ages, stays within 150-200g of carbs based on activity, and keeps fat around 55-65g. She plans to use the TDEE calculator to recalculate if her activity level changes significantly and monitors her weight weekly, adjusting calories by 100 if she trends up or down for two consecutive weeks.

Macro Ratio Reference Table by Goal

The top three ratios are used by this calculator. Other ratios shown for reference. Consult a healthcare provider before making significant dietary changes.

Tips and Complete Guide to Macro Nutrition

Understanding Macro Quality

Not all sources of a macronutrient are equal. For protein, complete sources (containing all essential amino acids) like eggs, fish, poultry, dairy, and soy are more effective for muscle building than incomplete plant sources alone. However, combining complementary plant proteins (rice + beans, hummus + pita) provides all essential amino acids. For carbohydrates, complex sources like whole grains, vegetables, legumes, and fruits provide fiber, vitamins, and sustained energy, while refined carbs (white bread, sugar) cause rapid blood sugar spikes. For fats, unsaturated fats from olive oil, nuts, avocado, and fatty fish support cardiovascular health, while saturated fat from red meat and full-fat dairy should be limited to under 10% of total calories.

Timing Your Macros for Performance

While total daily macro intake matters most, timing can enhance performance and recovery. Before exercise (1-2 hours prior), consume easily digestible carbohydrates with moderate protein to fuel your workout — examples include oatmeal with fruit or a turkey sandwich. After exercise (within 2 hours), combine protein and carbohydrates in roughly a 1:3 ratio to support muscle repair and glycogen replenishment — a smoothie with whey protein and banana is ideal. Spreading protein intake across 4-5 meals of 20-40 grams each maximizes muscle protein synthesis throughout the day. Fat timing is less critical, but avoiding high-fat meals immediately before exercise prevents digestive discomfort.

Adjusting Macros for Special Dietary Needs

Different dietary approaches require different macro adjustments. Vegetarians and vegans should aim for the higher end of protein recommendations (1.2-1.6 g/kg) and combine plant protein sources throughout the day. People with diabetes may benefit from moderating carbohydrate intake to 40-45% of calories and choosing low-glycemic sources. Individuals with kidney disease should consult their nephrologist about protein intake, as high protein loads increase kidney workload. Pregnant and breastfeeding women need increased protein (71g+ daily) and should never restrict calories below 1,800. Use the protein calculator for weight-based protein recommendations that account for your activity level.

Building Meals from Macro Targets

Once you have your macro targets, build meals by starting with your protein source (the hardest macro to hit for most people), adding a carbohydrate source, including vegetables, and adding fat for flavor and satiety. For example, if your targets are 150g protein, 200g carbs, and 65g fat: each of your 4 meals should contain roughly 37g protein, 50g carbs, and 16g fat. A sample meal fitting this would be 140g chicken breast (35g protein), one cup brown rice (45g carbs), mixed vegetables (5g carbs), and one tablespoon olive oil for cooking (14g fat). Meal prepping 4-5 protein sources and 3-4 carb sources at the beginning of each week makes daily macro hitting significantly easier.

Common Mistakes to Avoid

• Neglecting protein intake: Protein is the most commonly under-consumed macronutrient. Aim for your protein target first when planning meals, as it supports muscle maintenance, immune function, and satiety. Falling short on protein while hitting carb and fat targets leads to poor body composition results.
• Eliminating entire macronutrient groups: Each macronutrient serves essential functions. Extreme restriction of any macro (zero-carb, zero-fat) can lead to nutrient deficiencies, hormonal disruption, poor exercise performance, and unsustainable eating patterns. Even on low-carb diets, consuming at least 50-100g of carbs ensures adequate brain function and fiber intake.
• Focusing on macros while ignoring micronutrients: You can hit your macro targets eating processed foods alone, but you would miss essential vitamins, minerals, and fiber. Aim for 80% of your macros from whole, nutrient-dense foods and allow 20% for foods you enjoy. This flexible approach is sustainable long-term.
• Changing macro ratios too frequently: Give any macro ratio at least 3-4 weeks before evaluating its effectiveness. Constantly switching between ratios prevents you from identifying what actually works for your body. Track progress through weekly weight averages, monthly measurements, and how you feel and perform.
• Ignoring fiber intake: While tracking macros, ensure you consume at least 25g of fiber daily for women and 38g for men. Fiber supports digestive health, blood sugar control, and satiety but is often overlooked when focusing solely on protein, carbs, and fat grams.

Frequently Asked Questions