Macro Calculator
Find your daily calories and grams of protein, carbs and fat to lose fat, maintain weight or build muscle.
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Quick Tip
Enter your age, sex, height and weight.
About This Tool
Why use Macro Calculator?
This macro calculator works out your daily calories and then splits them into grams of protein, carbohydrate and fat for your goal. It estimates your BMR with the Mifflin-St Jeor equation, multiplies by your activity level to get TDEE, then applies a 20% deficit for fat loss or a 10% surplus for muscle gain.
Example: a 30-year-old woman, 68 kg and 165 cm, training moderately and aiming to lose fat. Her BMR is 1,400 calories and her TDEE is 2,170. A 20% deficit gives 1,736 calories a day. At 1.6 g of protein per kilogram that is 109 g of protein, 30% of calories from fat is 58 g, and the remaining calories give 195 g of carbohydrate.
Key Benefits
Mifflin-St Jeor equation
The equation most dietitians use for estimating resting metabolic rate, and more accurate than the older Harris-Benedict formula for modern populations.
Protein set by body weight
Protein is calculated per kilogram of body weight rather than as a percentage of calories, which is how the research actually frames intake targets.
Carbs fill the remainder
Protein and fat are set first because they have minimum requirements; carbohydrate takes whatever calories are left, which is the practical way to build a plan.
How to use Macro Calculator
- 1
Enter your age, sex, height and weight.
- 2
Choose the activity level that matches your typical week, not your best week.
- 3
Pick your goal: lose fat, maintain or build muscle.
- 4
Adjust protein per kilogram and the fat percentage if you follow a specific approach; carbohydrate fills the remaining calories.
- 5
Track your weight for two to three weeks and adjust calories if it is not moving as expected.
Best use cases
Set up a food tracking app with calorie and macro targets.
Work out how much protein you need to keep muscle while dieting.
Plan a lean bulk without excessive fat gain.
Understand why your weight stalled after several months of dieting.
How this tool compares
Macro Calculator FAQs
How many calories should I eat to lose weight?
A deficit of about 20% below your maintenance calories is a sustainable rate for most people, producing roughly 0.5–1% of body weight lost per week. Larger deficits lose weight faster but are harder to sustain and cost more muscle, especially without adequate protein and resistance training.
How much protein do I actually need?
Around 1.6 g per kilogram of body weight supports muscle growth for most people training regularly, and up to 2.2 g per kilogram is useful when dieting, because higher protein preserves muscle in a deficit and keeps you fuller. The 0.8 g per kilogram RDA is a minimum to avoid deficiency, not a target for athletes.
Do macros matter, or just calories?
Calories determine whether you gain or lose weight; macros influence what that change consists of and how you feel. Adequate protein preserves muscle, adequate fat supports hormone production, and carbohydrate fuels hard training. The same calorie total can produce very different results depending on the split.
Why has my weight loss stalled?
As you lose weight your BMR falls, so your original calorie target may now be close to maintenance. Recalculate with your current weight. Day-to-day water retention also masks fat loss for weeks at a time, so judge progress on a two to three week average rather than a single reading.
Should I eat the same macros on rest days?
Keeping intake consistent is simpler and works well for most people, since the weekly total is what drives results. Some prefer slightly more carbohydrate on training days and less on rest days, but this is a refinement — consistency across the week matters far more than daily precision.
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