How to Calculate Macros: Step-by-Step Grams per Kilogram Formula for Protein, Fat and Carbs

To calculate macros, set your calories first, then protein at roughly 1.6-2.2 g per kg of body weight, then fat at roughly 0.6-1.0 g per kg. Carbs get everything that is left. The formula is Carbs (g) = [Calories - (Protein g x 4 + Fat g x 9)] / 4.

That is the whole method, and it works the same whether you are cutting or bulking. If you are still sorting out the calorie side, start with our guide to energy balance, fat loss and bulking. If you would rather skip the arithmetic, the macro calculator does it for you. Below, you will see why grams per kilogram beat the usual 40/40/20 percentages, and three worked examples you can copy.

What is the grams per kg macro formula?

Four steps. Do them in order.

Step 1: Set your calorie target. You need a number for how much you will eat per day. Estimate maintenance with the calorie calculator, then go below it to cut or above it to gain. How far to go is covered in setting an optimal caloric deficit and lean bulking. Our guide to TDEE explains where the maintenance number comes from.

Step 2: Set protein. Multiply body weight in kg by 1.6-2.2. Multiply those grams by 4 to get protein calories.

Step 3: Set fat. Multiply body weight in kg by 0.6-1.0. Multiply those grams by 9 to get fat calories.

Step 4: Fill with carbs. Subtract protein calories and fat calories from your target. Divide what is left by 4. That is your carb grams.

Why 4 and 9? Protein and carbohydrate provide about 4 kcal per gram, fat about 9. These are the standard planning values, not exact absorbed energy, so treat the output as a starting estimate.

Why are grams per kg better than 40/40/20 percentages?

Because percentages hide what you actually care about.

Say you eat 2,000 kcal and pick a split with 30% protein. That is 600 kcal, or 150 g of protein. For a 50 kg person that is 3.0 g/kg. For a 70 kg lifter, about 2.1 g/kg. For a 90 kg lifter, about 1.7 g/kg. Same percentage, three very different doses.

It gets worse when calories change. Cut from 2,800 to 2,200 kcal on a 40% protein split and your protein drops by 60 g without you touching anything. A deficit is exactly when you want protein to stay high, not drift down with the calorie total.

The 40/40/20 split has a second problem. At 2,000 kcal, 20% fat is only about 44 g. For a 70 kg person that is about 0.63 g/kg, which is right at the edge of the range below, and it leaves no room for the foods that make a diet livable.

Percentages are not useless. They are a handy way to describe a finished plan (“I end up around 25% protein”). They are just a poor way to build one.

How much protein should I eat per kg?

Start with 1.6-2.2 g/kg of body weight per day. The evidence for the lower anchor is solid.

A 2018 meta-analysis of 49 trials with 1,863 participants in healthy adults found that protein supplementation increased fat-free mass and strength during resistance training. Beyond total intakes of about 1.62 g/kg/day, it found no further gain in fat-free mass (Morton et al., 2018). The ISSN position stand lands in a similar place: 1.4-2.0 g/kg/day is sufficient for most exercising individuals (Jager et al., 2017).

So why 2.2 at the top? Because the range is a buffer, not a target to chase. Studies differ in how they measure muscle, and individuals vary. Going to 2.0-2.2 g/kg costs little and covers the uncertainty.

When to move toward the top of the range

Hard deficits and low body fat. A systematic review of six studies in resistance-trained, lean athletes who were dieting concluded that protein needs are likely 2.3-3.1 g/kg of fat-free mass, scaled upward with the severity of calorie restriction and leanness (Helms et al., 2014). Note the denominator: fat-free mass, not total weight. And only six studies fed that conclusion, so hold it loosely.

The ISSN reaches a comparable view, saying higher intakes (2.3-3.1 g/kg/d) may be needed to maximise lean mass retention in resistance-trained people during low-calorie periods (Jager et al., 2017).

Total weight or lean mass?

For most people, total body weight is fine and keeps the formula simple. If you carry a lot of extra body fat, base the protein on a goal weight instead, or you will overshoot. If you are already lean and cutting hard, the top of the range makes sense. Want a quick number? The protein calculator gives one.

How much fat do I need?

Aim for about 0.6-1.0 g/kg body weight. I will be straight about this one: that range is a practical coaching convention, not a figure from a single trial.

What the research does say is that going very low is not free. A 2021 systematic review and meta-analysis of six intervention studies (206 men) found that low-fat diets reduced total testosterone, free testosterone and dihydrotestosterone compared with higher-fat diets, though the authors said further randomised trials are needed to confirm the effect (Whittaker and Wu, 2021). Six small studies, 206 men in total, men only. It does not prove that 0.5 g/kg will hurt your gains. It does suggest not living at the floor without a reason.

On the other side, physique-sport guidance for contest preparation suggests fat of about 10-25% of calories, so that the remaining energy can go to carbohydrate to support training during a deficit (Roberts et al., 2020). That is guidance for competitors in prep, so it is a reference point and not a rule for everyone.

In practice, I would start around 0.8 g/kg and move within the range depending on food preference. Love ghee, paneer and nuts? Sit nearer 1.0 and cut carbs a little. Love rice and roti? Sit nearer 0.6-0.7 and keep more carbs.

How do I calculate carbs?

You do not choose carbs. You subtract.

1. Protein grams x 4 = protein kcal.
2. Fat grams x 9 = fat kcal.
3. Calories minus both = carb kcal.
4. Carb kcal / 4 = carb grams.

That is why the method always adds up: carbs absorb any rounding, so the total lands exactly on your calorie target.

Do carbs need to be high? Probably less than you have been told. A 2022 systematic review of 49 studies found carbohydrate intake did not improve performance in most trials: acutely, higher carbs did not help in 13 studies and helped in 6 (mostly with fasted control groups and workouts above 10 sets per muscle group), and longer-term strength changes were not influenced by carb intake in 15 of 17 studies (Henselmans et al., 2022). Its conclusion was that carbs per se are unlikely to affect strength training performance in a fed state in workouts of up to 10 sets per muscle group, with higher volumes possibly benefiting.

The practical read: carbs are the flexible dial. Many people simply feel better training with a decent amount of them, and that is a valid reason. It is just not a physiological requirement for every session.

Worked examples: 70 kg, 80 kg and 90 kg lifters

These are illustrative targets, not prescriptions. Calories are assumed for the example; use your own from the calorie calculator.

70 kg lifter, cutting at 2,300 kcal. Protein 2.0 g/kg = 140 g (560 kcal). Fat 0.8 g/kg = 56 g (504 kcal). Carbs = (2,300 - 560 - 504) / 4 = 1,236 / 4 = 309 g.

80 kg lifter, lean bulking at 2,800 kcal. Protein 1.8 g/kg = 144 g (576 kcal). Fat 0.9 g/kg = 72 g (648 kcal). Carbs = (2,800 - 576 - 648) / 4 = 1,576 / 4 = 394 g.

90 kg lifter, cutting at 2,700 kcal. Protein 2.0 g/kg = 180 g (720 kcal). Fat 0.8 g/kg = 72 g (648 kcal). Carbs = (2,700 - 720 - 648) / 4 = 1,332 / 4 = 333 g.

Lifter	Calories	Protein	Fat	Carbs	Approx. split (P/F/C)
70 kg, cut	2,300	140 g	56 g	309 g	24 / 22 / 54
80 kg, bulk	2,800	144 g	72 g	394 g	21 / 23 / 56
90 kg, cut	2,700	180 g	72 g	333 g	27 / 24 / 49

Notice the percentages come out different for each person. That is the point: the grams are anchored to the body, and the percentages are just what falls out afterward.

How do I turn these numbers into Indian meals?

A common problem on a vegetarian Indian diet is that the carbs arrive easily and the protein does not. Dal and rice together are mostly carbohydrate. That is fine for the carb target, but you will probably need dedicated protein foods: paneer, curd or hung curd, milk, soya chunks, eggs if you eat them, chicken or fish if you are not vegetarian, and a whey or plant protein scoop when the day runs short.

A simple way to plan: place your protein first at each meal, then add roti or rice to fill the carb number, then count the cooking oil. If appetite is low in summer heat, liquid options like lassi or a shake can help you land the numbers without forcing food.

If you want a full day laid out, see our free diet plan. Getting the portions right is easier with a kitchen scale, which is the subject of food logging precision.

What if the numbers do not fit?

Two things can go wrong.

Carbs come out tiny or negative. Your calorie target is too low for your protein and fat. Lower fat toward 0.6 g/kg, use the lower end of protein, or raise calories a little. Do not just delete carbs and hope.

You cannot hit the numbers every day. You do not have to. Protein is the one to protect daily. Fat and carbs can drift within a range, and your weight trend responds to the weekly average. If strict tracking wears you down, see our piece on flexible dieting and long-term adherence.

How do I adjust after a few weeks?

Run the plan for 2-3 weeks. Weigh yourself on the same mornings and look at the weekly average, not single days. If your trend is not moving the way you intended, change calories by about 100-200 kcal and take that change from or add it to carbs. Leave protein and your fat floor alone.

Recalculate when your body weight has changed by several kilograms or your training load changes a lot. The formula scales with you, which is the main reason to use it.

When to see a doctor or dietitian

These are general guidelines for healthy adults. If you have kidney disease, diabetes, a history of disordered eating, are pregnant or breastfeeding, or are under 18, talk to a doctor or registered dietitian before setting your own protein, fat and calorie targets. Counting and restricting food can worsen disordered eating in some people, so if tracking makes you anxious, stop and get support.