Macro Calculator
Enter your body details, activity level and calorie goal to get a personalised daily macronutrient split — protein, carbs and fat in grams.
Reviewed by the ToolNestr Editorial Team — July 2026
Enter your details and calorie target to see your macros.
About macro targets
Macros make up all the calories you eat. Protein, carbohydrates and fat each play distinct roles in your body. Getting the right balance helps you feel energised, build or retain muscle, manage hunger and perform at your best. While total calorie intake drives weight change, your macro split determines how that weight loss or gain affects your body composition. This calculator starts from your TDEE (based on your body stats and activity) so you can set a custom calorie target, then splits it according to your chosen diet style. For more on your starting point, check the TDEE Calculator or Calorie Calculator.
⚕️ For general information only — not medical advice.
How it works
This calculator takes your daily calorie target and divides it across protein, carbohydrates and fat according to the percentage split you select. Each macro has a fixed calorie-per-gram value: protein and carbs each provide 4 calories per gram, while fat provides 9 calories per gram. For example, on a 2,000-calorie balanced split (30/40/30), you would get 150 g of protein, 200 g of carbs and 67 g of fat. The calculator also uses your body weight and activity level to suggest a sensible calorie target using the Mifflin-St Jeor BMR equation, so you can see what a maintenance or deficit level looks like before adjusting manually.
The formula explained
Each macro is calculated using simple arithmetic from your total calorie goal:
Protein (g) = (total calories × protein%) ÷ 4
Carbs (g) = (total calories × carb%) ÷ 4
Fat (g) = (total calories × fat%) ÷ 9
The calculator also estimates your TDEE from your body stats so you can set an informed calorie target. If you want to lose weight, start 300–500 calories below TDEE. For muscle gain, add 300–500 calories on top.
Worked example
A 28-year-old man, 180 cm, 82 kg, moderately active, wants to eat at maintenance (~2,775 cal/day) with a balanced split.
Muscle-building lifter
Use the High Protein split to ensure enough amino acids for muscle protein synthesis while keeping carbs moderate for workout fuel.
Keto dieter
Select the Keto split to get a very low carb, high fat breakdown that supports ketosis while keeping protein adequate to prevent muscle loss.
Meal prep enthusiast
Plan weekly meals around precise gram targets so each container hits your macros. Batch cooking becomes far more effective with clear numbers.
Dietitian
Quickly generate sample macro targets for clients based on their calorie needs and preferred eating style, saving time in consultations.
How to use this calculator
Set your calorie target
Enter your daily calorie goal. Get a starting point from our TDEE or Calorie Calculator if you are unsure what target to use.
Pick a split style
Choose from Balanced, High Protein, Low Carb or Keto. Each preset reflects a well-known dietary approach with different macro priorities.
Read your grams
See your daily targets for protein, carbs and fat in grams. Use a tracking app to log your food and hit these numbers consistently.
Tips for hitting your macros
Prioritise protein
Even if you miss your other targets, hitting your protein goal is most important for body composition. Aim for 1.6–2.2 g per kg of body weight if you are active.
Use a food scale
Eyeballing portions is notoriously inaccurate. A simple digital kitchen scale will dramatically improve how well you hit your macro targets each day.
Adjust based on feedback
Your macro split is a starting hypothesis. If you feel lethargic, try more carbs. If you are hungry between meals, try more protein or fat. Listen to your body and adjust.
Related tools
Frequently asked questions
What are macronutrients?
Macronutrients (macros) are the three main calorie-providing nutrients: protein (4 cal/g), carbohydrates (4 cal/g) and fat (9 cal/g). Your body needs all three in different proportions depending on your goals.
Which macro split should I choose?
Balanced (30/40/30) works for most people. High-protein (40/30/30) is great for muscle building and fat loss. Low-carb (35/20/45) suits keto-adapted individuals. Keto (20/5/75) is for strict ketogenic diets.
How much protein do I need?
For general health, 0.8 g per kg of body weight is the minimum. For active individuals and muscle building, 1.6–2.2 g per kg is recommended. Higher protein intakes also help with satiety during weight loss.
Do macros matter more than total calories?
For weight change, total calories matter most. But macronutrient balance affects body composition, energy levels, hunger and adherence. Getting enough protein is especially important during weight loss.
Can I use this for keto?
Yes — select the Keto split and the calculator will set very low carbs (5%) with high fat (75%) and moderate protein (20%), keeping you in nutritional ketosis range.
Sources & references
This tool uses standard formulas and reference values from:
- • NIH / National Institutes of Health and CDC reference values and formulas. nih.gov
- • Peer-reviewed equations (e.g. Mifflin-St Jeor, Harris-Benedict) as originally published.
- • ACOG for pregnancy, ovulation and due-date methodology. acog.org
Not medical advice. Estimates only — consult a qualified healthcare professional for any personal health decision.