How to calculate macros
for weight loss

Work in this order: calories (maintenance minus 10–20%), then protein (1.8–2.2 g per kg), then fat (0.6–1.0 g per kg), and carbohydrate takes whatever calories remain. Protein and carbs are 4 kcal per gram, fat is 9.

Step 1: calories

Start from maintenance and take 10–20% off. If you do not know your maintenance, estimate it as bodyweight in kg × 30 (sedentary) to × 35 (training several times a week), then correct it against two weeks of real data. The full method is in how many calories to lose weight.

Step 2: protein, which is not negotiable

Set protein at 1.8–2.2 g per kg of bodyweight. This is higher than the maintenance recommendation on purpose: a deficit is precisely when the body is most willing to break down muscle, and a high protein intake alongside resistance training is the argument against it.

If you are carrying a lot of fat, calculate from a target weight rather than current weight — protein need tracks lean mass.

Step 3: fat, with a floor

Fat is required, not optional: hormone production and the absorption of vitamins A, D, E and K all depend on it. Set it at 0.6–1.0 g per kg and do not go below about 0.5 g/kg regardless of how tempting the spare calories look.

Step 4: carbohydrate takes the remainder

Carbs are the adjustable one. They are also what fuels hard training, which is why cutting them to nothing in a deficit tends to produce a fortnight of poor sessions followed by a plateau you blame on your metabolism.

Worked examples

	65 kg	80 kg	95 kg
Maintenance (training 4×/wk)	2,275	2,800	3,325
Target (−18%)	1,865	2,295	2,725
Protein (2.0 g/kg)	130 g · 520 kcal	160 g · 640 kcal	190 g · 760 kcal
Fat (0.8 g/kg)	52 g · 468 kcal	64 g · 576 kcal	76 g · 684 kcal
Carbs (remainder)	219 g	270 g	320 g

Sanity-check the arithmetic on any target you are given: protein grams ×4, plus fat grams ×9, plus carb grams ×4 should equal the calorie target. A surprising number of published macro splits do not.

How precise does this need to be?

Less than most people assume. Hitting protein within about 10 g and calories within about 100 is close enough to produce every result the plan was designed for. The extra precision beyond that buys very little and costs the thing that actually matters, which is whether you are still logging in week six.

What does matter is the consistency of the measurement, not its accuracy. A slightly wrong number applied every day still shows you a trend. A perfect number applied on four days out of seven shows you nothing.

Common ways this goes wrong

• Setting carbs first. Carbs are the buffer, not the anchor. Set protein and fat, let carbs absorb the variation.
• Percentage splits like 40/30/30. They ignore bodyweight entirely, so the same split gives a 55 kg person and a 100 kg person wildly different protein per kg.
• Dropping fat to the floor to keep carbs high. Works for a few weeks, then stops being pleasant.
• Never recalculating. Ten kilos down is a different set of numbers.

Fibre and micronutrients, briefly

Aim for around 30 g of fibre a day. It is the single biggest lever on how a deficit feels, and it is the thing people quietly lose when they cut carbs to hit a macro target. Tracking micronutrients as well as macros is worth doing for a week or two at the start of any deficit, purely to find out which one you are missing.

Common questions

How do I calculate my macros for weight loss?

Set calories 10 to 20 percent below maintenance. Then set protein at 1.8 to 2.2 grams per kilogram of bodyweight, fat at 0.6 to 1.0 grams per kilogram, and give the remaining calories to carbohydrate. Protein and carbohydrate supply 4 calories per gram, fat supplies 9.

What is the best macro split for fat loss?

There is no single best percentage split, because percentages ignore bodyweight. Setting protein and fat per kilogram of bodyweight and letting carbohydrate take the remainder produces a better result than any fixed ratio such as 40/30/30.

Do I need to hit my macros exactly?

No. Within about 10 grams on protein and 100 calories on the total is close enough for the plan to work. Consistency over weeks matters far more than precision on any single day.

Should carbs be low for weight loss?

Not necessarily. Weight loss is driven by the calorie deficit, not by carbohydrate level. Carbohydrate mainly determines training quality, so cutting it aggressively often costs performance without improving fat loss.

These are general guidelines for healthy adults, not medical advice. If you are pregnant, under 18, managing a health condition, or have a history of disordered eating, talk to a GP or a registered dietitian before changing how much you eat.

Read next: How much protein do I need? Calorie deficit guide Calories to lose weight