Reckonary / Health / Macros

Macro calculator

Daily macros
30
Moderate

Daily calories

2,759
Protein207 g
Fat92 g
Carbs276 g

A macro calculator turns your daily calorie needs into grams of the three macronutrients — protein, fat, and carbohydrates. Knowing the grams, not just the calories, makes it far easier to plan meals, read food labels, and stay on track with a goal like losing fat or building muscle.

How this calculator works

It starts with the Mifflin-St Jeor equation, a well-tested formula that estimates the calories your body burns at rest from your weight, height, age, and sex. Multiplying that by your activity level gives your total daily calories. Your goal then adjusts the target: maintain keeps it as is, lose subtracts 500 calories a day, and gain adds 500. Finally the calories are split 30% protein, 30% fat, and 40% carbs and converted to grams.

An example

A 30-year-old man who weighs 80 kg, is 180 cm tall, and trains a few times a week burns about 2,759 calories a day. To maintain that, the split works out to roughly 207 g of protein, 92 g of fat, and 276 g of carbs. Switch the goal to lose and every number scales down with the lower calorie target.

Good to know

  • Protein and carbs provide 4 calories per gram; fat provides 9.
  • The 500-calorie change is a common rule of thumb for steady, not extreme, weight change.
  • Real needs vary with body composition, training, and health, so treat these as a starting point.

Frequently asked questions

How are my macros calculated?

First we estimate your daily calories with the Mifflin-St Jeor equation and your activity level. Then we split those calories 30% protein, 30% fat, and 40% carbs, and convert to grams at 4 calories per gram for protein and carbs and 9 for fat.

Why does my goal change the numbers?

Maintaining uses your full daily calories. Losing subtracts 500 calories a day, and gaining adds 500. The macro split stays the same, so the grams scale with the new calorie target.

What activity level should I pick?

Sedentary is a desk job with little exercise. Light is one to three workouts a week, moderate is three to five, active is six or seven, and very active is hard training or a physical job most days.

Is the 30/30/40 split right for everyone?

It is a balanced starting point that works for most people. Athletes, low-carb diets, and specific medical needs may call for a different ratio, so adjust with a professional if you have particular goals.

Last reviewed June 2026. Calories use the Mifflin-St Jeor equation. For general guidance, not medical or dietary advice.