BodyCalc

Macro Calculator

Get daily protein, fat and carbohydrate targets in grams, with the percentage of calories each one takes.

GoalFat loss
GoalFat loss based on 2,662 kcal/day maintenance
Daily calories2,130 kcal/day
Protein165 g (31% of calories) 2.2 g per kg of body weight
Fat59 g (25% of calories) 25% of calories
Carbohydrate234 g (44% of calories) fills the remaining calories
Fibre30 g 14 g per 1,000 kcal
Units
How the split shifts between the three goals, at 75 kg and moderate activity
  • Fat loss40% carbs 2.2 g/kg protein
  • Maintain45% carbs 1.8 g/kg protein
  • Muscle gain50% carbs 1.6 g/kg protein

Illustrative shares for these inputs - the calculator above prints the exact grams for your own numbers.

What macronutrients are

Macronutrients are the three energy-providing parts of food: protein, fat and carbohydrate. Alcohol is a fourth source of calories, but it is not a macronutrient you can build a plan around. Each gram of protein or carbohydrate supplies about 4 kcal, each gram of fat about 9 kcal, and each gram of alcohol about 7 kcal.

Macro targets matter less than total calories for weight change, and much more than total calories for body composition, training quality and hunger. Two people can eat the same 2,100 kcal and feel completely different: the one eating 160 g of protein, plenty of fibre and a reasonable amount of fat usually finds the plan far easier to hold.

MacronutrientEnergy per gramMain jobs
Protein4 kcalrepair and build muscle, keep you full, protect lean mass in a deficit
Fat9 kcalhormones, cell membranes, vitamin absorption, food flavour
Carbohydrate4 kcalfuel for hard training, brain and high-intensity work
Alcohol7 kcalnone nutritionally; it also blunts recovery and appetite control

How this calculator sets your split

The calculator starts from your maintenance calories, applies the goal you selected - about 20% below for fat loss, 10% above for muscle gain, unchanged for maintenance - and then allocates protein first. Protein is set by body weight rather than by percentage: 2.2 g per kilogram while cutting, 1.8 g while maintaining and 1.6 g while gaining, because a percentage-based protein target breaks down when calories are low.

Fat is fixed at roughly 25% of calories, comfortably above the intake where hormonal and vitamin-absorption problems appear. Carbohydrate then fills whatever energy remains after protein and fat, which is why carbohydrate grams move the most when calories change. The percentages you see at the end are a result of that arithmetic, not an assumption built in beforehand.

GoalCalorie changeProteinFatCarbs
Fat lossabout -20%2.2 g/kg25% of caloriesremainder
Maintain0%1.8 g/kg25% of caloriesremainder
Muscle gainabout +10%1.6 g/kg25% of caloriesremainder

Why protein comes first

Protein is the one macro with a well-supported minimum per kilogram, and the minimum is higher than most people eat. The evidence base for muscle retention during a deficit points to 1.6 to 2.4 g per kilogram per day, with the higher end helping leaner and more experienced lifters. Above about 2.6 g per kilogram there is little further benefit for most people, though it is not harmful in healthy adults.

Protein also does the most work for appetite: it is the most satiating macro, has the highest thermic effect of food, and helps hold muscle when calories are cut. That is a better reason to hit the number than any claim about metabolism, which is modest at best.

Body weight2.2 g/kg (cutting)1.8 g/kg (maintaining)
60 kg (132 lb)132 g108 g
75 kg (165 lb)165 g135 g
90 kg (198 lb)198 g162 g
105 kg (231 lb)231 g189 g

Fat and carbohydrate: where the flexibility lives

Fat has a practical floor rather than an ideal target. Around 0.5 to 0.6 g per kilogram per day covers essential fatty acids and vitamin absorption, and most people feel better and train better with 20% to 30% of calories coming from fat. Below that, hunger tends to rise and food gets monotonous; well above it, carbohydrate is squeezed and hard training suffers.

Carbohydrate is the opposite: the requirement depends almost entirely on how much hard training you do. A person lifting three times a week and walking 8,000 steps can train well on 3 g per kilogram, while someone running 60 km a week may need 5 to 7 g per kilogram. This is why two people with identical calorie targets can end up with very different carbohydrate numbers, and neither of them is wrong.

Reading your macro result

The output gives you grams per day for each macro plus the share of calories it represents. Use the percentages as a sanity check, not a rule: a split landing at roughly 35% protein, 25% fat and 40% carbohydrate while cutting is normal and sensible, even though it does not look like the classic 40/30/30 headline.

The fibre row is a useful extra. Most adults fall well short of the 14 g per 1,000 kcal guideline, and hitting it usually means the food choices behind the numbers are good ones - vegetables, fruit, legumes and whole grains rather than refined starch and oil.

RowWhat it meansHow to use it
Daily caloriesyour target after the goal adjustmentthe number that drives weight change
Proteinset from body weighthit this within about 10 g every day
Fat25% of caloriesa floor for hormones and vitamin absorption
Carbohydratewhatever energy is leftraise it on heavy training days if you prefer
Fibre14 g per 1,000 kcala marker of diet quality, not a target to force

Putting the numbers on a plate

Grams are easy to plan and hard to eat, so translate them once into a template and then stop counting every meal. A workable pattern for a 75 kg person cutting at 165 g protein: a palm-sized portion of a protein food at every meal, a thumb of fat, two fists of vegetables and a cupped hand of carbohydrate around training. That structure lands close to most plans without a scale.

Spread protein across three to five meals of roughly 30 to 50 g each rather than loading it all at dinner. The old idea of a strict 30-minute anabolic window is overstated, but evenly spread protein does make the daily total easier to hit and slightly improves muscle protein synthesis.

  • Build each meal around a protein source, then add fat and carbohydrate to fit the day.
  • Keep protein high on rest days, not just training days.
  • Place most carbohydrate around training if your sessions are hard.
  • Recheck the plan every 5 to 7 kg of weight change.

Frequently asked questions

How much protein do I need per day?

For a cut, 1.6 to 2.4 g per kilogram of body weight; for maintenance or a lean gain, 1.4 to 1.8 g per kilogram. A 75 kg person cutting is therefore looking at roughly 120 to 180 g a day, with about 165 g as the middle of that range.

Do macros matter more than calories?

For weight change, calories decide the outcome and macros shape the experience. For body composition - how much of the loss is fat rather than muscle - protein and training are the two inputs that matter most.

Can I eat all my protein in one meal?

You can hit the daily total that way, and it still supports muscle, but very large single doses are less efficient and usually less comfortable. Splitting it over three or four meals is the practical middle ground.

Is a low-carb or keto split better?

For fat loss at equal calories and equal protein, the evidence shows no meaningful advantage. Keto can help people who prefer the food or who find appetite easier to control without carbohydrate, and it makes hard training harder for most.

Do I need to count fibre?

Not daily. The 14 g per 1,000 kcal guideline is a useful quality check: if you are close to it, your food choices are usually varied enough for micronutrients too.

Should macros change on training days?

Optional. Holding the weekly totals steady and shifting 50 to 100 g of carbohydrate toward hard training days works well for people who train four or more times a week. Keep protein and calories constant either way.

Sources

  1. Morton RW et al., A systematic review of protein supplementation and resistance training
  2. Helms ER et al., Evidence-based recommendations for natural bodybuilding contest preparation
  3. Dietary Guidelines for Americans
  4. Mifflin MD et al., predictive equation for resting energy expenditure

Formulas and thresholds are taken from the sources above. They are a starting point for adults, not a diagnosis.

Last reviewed September 12, 2026. How we calculate · Editorial policy