About the Macro Calculator
Macros are the three nutrients that supply calories: carbohydrate, protein and fat. This calculator estimates how many calories you burn in a day using the Mifflin–St Jeor formula and your activity level, adjusts them for your goal, and splits them into grams of carbs, protein and fat. Choose a balanced, lower-carb, high-protein or keto split, or set your own percentages, and see the grams for each meal if you eat three, four or five times a day. It also shows protein per kilogram of body weight. These are estimates that can be off by 10 percent or more for an individual, and the goal adjustments are common starting points, not prescriptions. Not for pregnancy, illness, teens under 15 or eating-disorder recovery. For general information only, not medical advice.
Updated September 2026
How to use the Macro Calculator
- 1Choose your sex and units, then enter age, height and weight.
- 2Pick your activity level and a goal, or type your own calories per day.
- 3Choose a macro split, or Custom and enter percentages that add up to 100.
- 4Read your daily calories and the grams of carbs, protein and fat.
- 5Pick 3, 4 or 5 meals to see the grams per meal, then press Copy targets.
What macros are
Carbohydrate is the body's quick fuel, found in grains, fruit, starchy vegetables and sugar. Protein builds and repairs tissue and is found in meat, fish, eggs, dairy, beans and soy. Fat supplies concentrated energy and helps absorb some vitamins. Counting macros means tracking grams of these three, not just total calories.
From calories to grams
The calculator estimates your basal metabolic rate with the Mifflin–St Jeor equation, multiplies it by an activity factor from 1.2 to 1.9 for your daily burn, and then applies your goal: 20 percent less to lose, 10 percent more to gain. The calories are shared out by your split and divided by 4 for carbs and protein or by 9 for fat. If you already know your calorie target, type it in and it replaces the estimate.
For a deeper look at daily energy, the Calorie Calculator shows several weight-change targets.
Choosing a split
Pick the one you can stick to. Adherence matters more than the exact numbers.
- Balanced: 40% carbs, 30% protein, 30% fat
- Lower carb: 25% carbs, 35% protein, 40% fat
- High protein: 30% carbs, 40% protein, 30% fat
- Keto: 5% carbs, 25% protein, 70% fat
- Custom: any three percentages that add up to 100
Turning grams into meals
Grams are easier to use when they are spread across the day. The per-meal view divides each target by 3, 4 or 5 and rounds to whole grams. Check labels for grams per serving and adjust portions to hit your numbers. If you want a check on body composition, use the Body Fat Calculator or the BMI Calculator. The Sleep Calculator can help with recovery, and the Percentage Calculator handles simple comparisons. This is not medical advice.
Features
- Calories from the Mifflin–St Jeor formula
- Lose, maintain and gain goals, or your own calorie target
- Balanced, lower-carb, high-protein, keto and custom splits
- Grams and calories for carbs, protein and fat
- Per-meal grams for 3, 4 or 5 meals
- Protein in grams per kg of body weight
- Metric or imperial units
- Runs in your browser
Frequently asked questions
What are macros?
Macros, short for macronutrients, are carbohydrate, protein and fat. Carbs and protein give about 4 calories per gram and fat gives about 9. Alcohol is sometimes counted as a fourth source, but it is not included here.
How do I calculate my macros?
First estimate your daily calories, then choose the share you want from carbs, protein and fat and divide each share by its calories per gram. For 2,000 calories at 40, 30 and 30 percent that gives 200 g of carbs, 150 g of protein and about 67 g of fat.
How much protein do I need per day?
Needs vary with size, activity and goals, and recommendations differ between health bodies. The page shows your protein in grams per kilogram of body weight for whichever split you choose, so you can compare it with the advice you have been given.
What is a good macro split for fat loss?
There is no single best split. Higher-protein splits are popular because protein tends to keep people full, and the Lose goal cuts calories by 20 percent as a starting point. A dietitian can tailor it to you.
Are calories from carbs, protein and fat the same?
A gram of carbs or protein has about 4 calories and a gram of fat about 9, so grams and calories differ. The three also act differently in the body, which is why the split matters as well as the total.
How do I track macros per meal?
Choose 3, 4 or 5 meals and the page divides each target evenly, rounded to whole grams. You do not have to eat the same in every meal; the daily totals matter more.
Why must my custom percentages add up to 100?
Every calorie comes from one of the three macros, so the shares have to cover the whole day. If they do not add up, the page asks you to adjust them before showing grams.