Macro Calculator: Protein, Carbs and Fat for Your Goal

The short answer

Set protein from your body weight, give fat about a quarter of your calories, and let carbs fill the rest. For most people who lift, that's 1.6 to 2.2 g of protein per kg / 0.7 to 1 g of protein per pound of body weight a day, a little more while dieting. Your macro percentages then follow from your calories, so they change when your calories do.

How to use the macro calculator

1. Choose metric or imperial units.
2. Enter your gender, age, height and body weight, and pick the activity level that matches a typical week.
3. Pick your goal: lose fat, maintain, or build muscle.
4. Keep "Estimate them for me" to use the same calorie estimate as the daily calorie needs calculator, or choose "I know my target" and type in your own number.
5. Choose a protein level and a fat share. The preselected ones suit most people.

You get grams, calories and the share of calories for each macro, protein per meal for three to five meals, and the same targets as a percentage split you can enter in GymEvo.

How the calculator works

No calculator can measure your metabolism, so the honest answer to "which macro calculator is most accurate" is the one whose steps you can check. Here are all four.

1. Calories

Unless you enter your own target, the calculator uses the same estimate as the daily calorie needs calculator: resting energy from the Mifflin-St Jeor equation, multiplied by an activity factor, then 20% less to lose fat or 20% more to build muscle.

That fixed 20% is a simple default. It's more than a body recomposition or a lean bulk needs, and both guides work out a smaller number from your maintenance calories. If you have that number, choose "I know my target" and enter it.

2. Protein, set by body weight

Protein is the one macro tied to your body rather than to your calories. A large review of protein and lifting found that muscle gains stopped increasing at around 1.6 g per kg / 0.7 g per pound of body weight a day, so that's the floor here and anything above it is margin.

A diet changes the picture. The sports nutrition society's position on protein puts most people who exercise at 1.4 to 2 g per kg / 0.6 to 0.9 g per pound a day and says lifters in a calorie deficit may need more to hold on to muscle, which a review of dieting lifters also found. That's why "lose fat" starts at 2 g per kg / 0.9 g per pound. The two higher options are for lean people cutting hard.

3. Fat, as a share of calories

Fat is preselected at 25% of your calories, and you can choose between 20% and 35%. That's the range the US Dietary Guidelines list as acceptable for adults, and a review of diets for natural bodybuilders suggests a similar 15% to 30% while dieting.

On a small calorie target, a percentage can drop fat lower than most people find satisfying, so the calculator never goes below 0.5 g per kg / 0.2 g per pound of body weight, the bottom of the range in a review of nutrition for building muscle. If it has to raise fat to that floor, the result says so.

4. Carbs fill the rest

carbs (g) = (calories - protein (g) x 4 - fat (g) x 9) / 4

Protein and carbohydrate count as 4 kcal per gram and fat as 9, the general factors US nutrition labels use. If protein and fat already use up your calories, the calculator tells you instead of showing a negative number. In "build muscle" mode it also points out when carbs come in under 3 g per kg / 1.4 g per pound, because the same review of building muscle recommends at least that much.

The split you can enter in GymEvo

GymEvo sets macro targets as whole percentages in steps of 5 that add up to 100. The calculator rounds your targets to the nearest such split, giving any leftover step to the share that was closest to rounding up, and shows how many grams that split works out to at your calories.

Worked examples

Maintaining, for a man

Protein is under a fifth of his calories, far from the 30% or 40% that fixed splits often assume, and he still gets all the protein the research supports.

Losing fat, for a woman

The method is the same for women. Only the inputs change.

Here protein is over a third of the calories. Same rules, very different percentages, because the calories are lower and the protein target goes up in a deficit.

Why fixed ratios like 40/30/30 can mislead

Splits like 40/30/30 (40% carbs, 30% protein, 30% fat) or 40/40/20 hand out protein as a share of calories. But your protein needs follow your body weight, not your calories, so the same ratio gives very different amounts depending on how much you eat. For an 80 kg / 175 lb lifter on a 40/30/30 split:

• At 1,500 kcal, 30% protein is about 113 g, or 1.4 g per kg / 0.6 g per pound. That's below the 2 g per kg / 0.9 g per pound that suits most people in a deficit, right when holding on to muscle matters most.
• At 3,500 kcal, it's about 263 g, or 3.3 g per kg / 1.5 g per pound. That's well past the point where more protein builds more muscle, and those calories could have been carbs for training.

A 40/40/20 split puts 40% on protein. That lands closer on a diet, about 150 g at 1,500 kcal, but even further over on a bulk.

Ratios aren't wrong as a way to enter targets. GymEvo uses percentages too. They just make a poor starting point. Work out protein from your body weight first, then turn the result into a ratio, which is what this calculator does.

Tracking your macros in GymEvo

A target only helps if you track against it. GymEvo's food log is free: barcode scanning, a food database, quick calorie and macro entries, and macros per meal and per day. You set calories and macro percentages in the nutrition goal screen, and the calorie target can follow your weigh-ins automatically. AI estimates from a meal photo or a spoken description are part of Premium. See GymEvo's free calorie counter.

The nutrition goal screen: macro targets move in steps of 5% and have to add up to 100%.

For the day-to-day side, how to count macros covers weighing, logging and what precision actually matters.

Assumptions and limitations

• The result is a starting estimate, not a measurement. After 2 to 3 weeks of logging food and weighing yourself, your own trend tells you whether the calories are right.
• The calorie estimate is for adults aged 18 to 100. The original Mifflin-St Jeor study included ages 19 to 78, so estimates outside that range may be less reliable.
• The calculator doesn't split a target below 1,000 kcal a day. The NIDDK Body Weight Planner warns that food-group targets and nutrient recommendations will not be met below that level.
• If you're pregnant or breastfeeding, have kidney disease, take medication for diabetes, or have a history of disordered eating, set your targets with a doctor or registered dietitian rather than a calculator. Tracking macros closely isn't a good idea for everyone.