🥩 Macro Calculator

How it works

Your daily calories come from three macronutrients — protein, carbohydrates, and fat — and the split between them shapes how you feel, perform, and look, even when total calories stay the same. Protein builds and preserves muscle, carbs fuel activity, and fats support hormones and satiety. A macro calculator translates a calorie target into grams of each, so you can plan meals instead of guessing.

This calculator estimates your daily calorie burn (TDEE) from your age, sex, height, weight, and activity level, adjusts for your goal — fat loss, maintenance, or muscle gain — and divides the calories into a protein-first split.

The formula

TDEE starts with the Mifflin-St Jeor estimate of resting burn: men use 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5, women use the same formula with − 161 instead of + 5. That resting number is multiplied by an activity factor (roughly 1.2 for sedentary up to 1.9 for very active). Then the calories are split using the energy densities: protein = 4 cal/g, carbs = 4 cal/g, fat = 9 cal/g. A common split: 1.6–2.2 g protein per kg, 0.5–1 g fat per kg, remaining calories as carbs.

Worked example

A 30-year-old woman, 70 kg and 165 cm, moderately active, wants gradual fat loss. Her TDEE works out to roughly 2200 cal/day, so a 400-calorie deficit sets an 1800-calorie target. Protein at 2 g/kg = 140 g (560 cal), fat at 0.8 g/kg = 56 g (504 cal), leaving 1800 − 1064 = 736 cal for carbs = 184 g. Her daily target: roughly 140 g protein, 184 g carbs, 56 g fat.

Frequently asked questions

Do macros matter more than total calories?
No — calories decide whether you gain or lose weight; macros decide what kind of weight and how you feel. Nail calories first, then tune the split.

How much protein do I actually need?
For active people aiming to keep or build muscle, 1.6–2.2 g per kg of body weight per day is the well-supported range. Sedentary adults need less — around 1.2 g/kg is a sensible floor.

Can I build muscle and lose fat at the same time?
Beginners often can, especially with high protein and strength training. Experienced lifters usually do better picking one goal.

How to read your macro targets

Macros are grams first and percentages second. Protein and carbohydrate provide about 4 calories per gram and fat about 9, and the calculator builds your targets in a deliberate order. Protein is anchored to your body weight, because muscle repair and retention depend on the absolute amount, not on what share of the plate it happens to be. Fat gets a floor, since very low fat intakes can interfere with hormone production and make meals unsatisfying. Carbohydrate then takes whatever calories remain, which is why it swings the most between low carb and high carb approaches. Percentages can mislead: 30 percent protein on a 1,400 calorie diet is only 105 grams, while the same 30 percent on 2,800 calories is 210 grams. If you train hard, your position within the recommended protein range matters too, with intakes around 1.6 to 2.2 grams per kilogram of body weight covering most muscle building and dieting situations. Fibre deserves a mention alongside the big three: roughly 14 grams per 1,000 calories eaten is a widely used target, and it is the first thing to suffer when macro targets are hit with processed food alone.

A worked example

Take a woman of 29 who weighs 80 kg and maintains her weight on about 2,300 calories. For steady fat loss she targets 1,850 calories. Protein at 2.0 grams per kilogram gives 160 grams, worth 640 calories. Fat at 60 grams, a moderate setting, gives 540 calories. That leaves 670 calories for carbohydrate, which at 4 calories per gram is 168 grams. Her day looks like this:

• Protein: 160 g, 640 calories
• Fat: 60 g, 540 calories
• Carbohydrate: 168 g, 672 calories
• Total: 1,852 calories, within rounding of her 1,850 target

Her protein stays where it would be at maintenance, which protects her muscle while she loses; the entire deficit has come out of fat and carbohydrate.

Common mistakes

• Setting protein as a percentage of calories. On a small calorie budget the percentage can look fine while the grams fall far short of what muscle needs.
• Driving fat to the floor. Below roughly 0.5 grams per kilogram of body weight for long stretches, expect hunger, poor food satisfaction and possible hormonal disruption.
• Forgetting the untracked calories: cooking oils, butter, dressings, alcohol at 7 calories per gram, and drinks. These routinely add 200 to 400 calories a day.
• Changing the targets every few days. Macro targets need two to three consistent weeks before the scale and the mirror can tell you whether they are working.
• Hitting the numbers with food that leaves you hungry and under nourished. Satiety, fibre and protein quality decide whether a perfect macro split survives contact with real life.

Frequently asked questions

Which macro matters most?

Protein, for most goals. It protects and builds muscle, keeps hunger down, and is the one target that should stay put whether you are cutting, maintaining or gaining. Set protein first, give fat a sensible floor, then let carbohydrate absorb whatever calories remain in your budget.

Do I need more protein while losing weight?

Generally yes. In a calorie deficit your body is tempted to burn some muscle along with fat, and higher protein intakes, roughly 1.6 to 2.2 grams per kilogram of body weight, measurably reduce that loss. It also helps with fullness, which makes the deficit easier to keep.

Is low carb or low fat better for fat loss?

When calories and protein are matched, studies find the difference between low carb and low fat diets is small. The approach that works is the one you can still be following in six months. Choose based on the foods you enjoy and how each pattern affects your hunger.

Should my macros change on rest days?

They can, but they do not have to. Some people eat more carbohydrate on training days and less on rest days while keeping the weekly total the same. For most people a single daily target is simpler and works just as well, since weekly intake drives the results.