acalculator

What should my macros be?

Choose how many calories you eat, or let the calculator estimate them, then set the share from carbs and protein. See the grams of each macronutrient a day.

Your numbers

Units
Sex
Multiplies your BMR by 1.2, 1.375, 1.55, 1.725 or 1.9.
250 calories a day for each 0.5 lb a week.
Adults: 45% to 65%.
Adults: 10% to 35%. Fat gets the rest (20% to 35% for adults).
More options
BMR formula
Protein a day
96 g

At 1,927 calories a day, eat about 96 g of protein, 241 g of carbs and 64 g of fat.

Carbs a day
241 g
Fat a day
64 g
Calories a day
1,927
Fat share
30%
Calories from protein
385
Calories from carbs
963
Calories from fat
578
Against the adult ranges
All three are inside the adult ranges.

Protein a day: 96 g. At 1,927 calories a day, eat about 96 g of protein, 241 g of carbs and 64 g of fat.

Where do your calories come from?

This calculator gives general information only. It is not medical advice and does not replace a doctor or other health care provider. Talk with a professional about your results. Terms of use

How to calculate

Splits daily calories into grams of protein, carbohydrate and fat (4, 4 and 9 calories per gram) by the chosen percentages, and checks them against the adult AMDR ranges.

Example with the default inputs (Daily calories Work them out, Sex Female, Age 30, Height 5 ft 5 in, Weight 150 lb, Activity Light: exercise 1 to 3 days, Goal Keep my weight, Carbs 50%, Protein 20%, BMR formula Mifflin-St Jeor): At 1,927 calories a day, eat about 96 g of protein, 241 g of carbs and 64 g of fat.

Method: Protein and carbs in grams = calories × share ÷ 4; fat in grams = calories × (100% − carbs − protein) ÷ 9. Calories are typed, or TDEE (BMR × activity factor) ± the goal.

  • Protein and carbohydrate give 4 calories per gram and fat gives 9 (Atwater factors).
  • Fat gets whatever share carbs and protein leave.
  • The ranges are the adult Acceptable Macronutrient Distribution Ranges (IOM 2005): protein 10–35%, carbs 45–65%, fat 20–35%.
  • Worked-out calories use Mifflin-St Jeor or the revised Harris-Benedict, the activity factors 1.2 to 1.9, and 500 calories a day per pound a week.
  • This is an estimate for planning, not medical advice.

Machine-readable copies: Markdown, JSON.

Worked examples

Each example is checked against the calculator on every build.

  1. Daily calories Work them out, Sex Female, Age 30, Height 5 ft 5 in, Weight 150 lb, Activity Light: exercise 1 to 3 days, Goal Keep my weight, Carbs 50,000 g, Protein 20,000 g, BMR formula Mifflin-St Jeor gives Calories a day 1,926.737388, Protein 96 g, Carbs 241 g, Fat a day 64 g, Fat share 30%, Against the adult ranges All three are inside the adult ranges..Source: Mifflin et al. 1990; 4, 4 and 9 calories per gram (USDA); hand calculation in content.mdx
  2. Daily calories I know them, Calories a day 2,400, Carbs 45,000 g, Protein 30,000 g gives Protein 180 g, Carbs 270 g, Fat a day 67 g, Fat share 25%, Calories from fat 600.Source: 4, 4 and 9 calories per gram (USDA); hand calculation in content.mdx
  3. Daily calories I know them, Calories a day 1,800, Carbs 20,000 g, Protein 35,000 g gives Protein 158 g, Carbs 90 g, Fat a day 90 g, Fat share 45%, Against the adult ranges Carbs 20% is under the 45% to 65% range. Fat 45% is over the 20% to 35% range..Source: IOM 2005 AMDR (carbs 45–65%, fat 20–35%); hand calculation in content.mdx
  4. Daily calories Work them out, Sex Male, Age 35, Height 5 ft 10 in, Weight 180 lb, Activity Moderate: exercise 3 to 5 days, Goal Lose 1 lb (0.45 kg) a week, Carbs 40,000 g, Protein 30,000 g, BMR formula Mifflin-St Jeor gives Calories a day 2,224.460212, Protein 167 g, Carbs 222 g, Fat a day 74 g.Source: Mifflin et al. 1990; 500 calories a day for 1 lb a week; hand calculation in content.mdx

How it works

1. Daily calories. Either you type them ("I know them"), or the calculator works them out:

  • BMR (Mifflin-St Jeor, the default), with weight in kilograms, height in centimetres and age in years: men 10 × weight + 6.25 × height − 5 × age + 5; women 10 × weight + 6.25 × height − 5 × age − 161.
  • Revised Harris-Benedict (under "More options"): men 88.362 + 13.397 × weight + 4.799 × height − 5.677 × age; women 447.593 + 9.247 × weight + 3.098 × height − 4.330 × age.
  • TDEE = BMR × activity factor: 1.2 (sedentary), 1.375 (light), 1.55 (moderate), 1.725 (very active) or 1.9 (extra active).
  • Daily calories = TDEE + goal: keep 0; lose 0.5 lb a week −250; lose 1 lb −500; lose 2 lb −1,000; gain 0.5 lb +250; gain 1 lb +500. These use 3,500 calories per pound of body weight (Wishnofsky, 1958).

If a loss goal takes away more calories than your TDEE (daily calories of 0 or less), there is no answer.

2. Shares. You set carbs % and protein %. Fat % = 100 − carbs % − protein %. If carbs and protein add up to more than 100%, there is no answer.

3. Grams a day.

  • Protein (g) = calories × protein % ÷ 100 ÷ 4
  • Carbs (g) = calories × carbs % ÷ 100 ÷ 4
  • Fat (g) = calories × fat % ÷ 100 ÷ 9

Protein and carbohydrate give 4 calories per gram and fat gives 9, the general factors of the U.S. food labelling rules (21 CFR 101.9). The calculator also shows the calories from each macro: calories × share ÷ 100.

4. Check against the adult ranges. Each share is compared with the Acceptable Macronutrient Distribution Range (AMDR) for adults (IOM, 2005), limits included:

  • Protein: 10 to 35% of calories
  • Carbohydrate: 45 to 65% of calories
  • Fat: 20 to 35% of calories

When you pick a loss goal and your daily calories come out under 1,200 (women) or 1,500 (men), a note warns you: this is the low end of the weight-loss diets in the 2013 AHA/ACC/TOS guideline. Typed calories under 1,200 get the same note (sex is not asked in that mode, so the lower limit applies). The note reads exactly: "This is under 1,200 calories a day, below the lowest diet the weight-loss guideline suggests." (with 1,500 for men).

The range check uses each share rounded to one decimal, the value the page shows, so 44.95% counts as 45% and is inside the carbohydrate range. When every share is inside, the text reads "All three are inside the adult ranges." Otherwise it lists each share outside, in the order protein, carbs, fat, as "Carbs 20% is under the 45% to 65% range." (one sentence per share, joined with a space).

The chart shows how your calories split between protein, carbs and fat.

Assumptions

  • Fibre and alcohol are not counted separately.
  • The ranges are for adults. Children, and people who are pregnant or breastfeeding, have other needs.
  • Nothing is rounded until the result is shown.
  • This calculator gives an estimate for planning. It is not medical advice. Talk to a doctor or a registered dietitian before a large change in diet, and if you have a health condition such as diabetes or kidney disease.

Worked examples by hand

Worked out from the body: a 30-year-old woman, 5 ft 5 in (165.1 cm), 150 lb (68.039 kg), lightly active, keeping her weight, 50% carbs and 20% protein. BMR = 680.39 + 1,031.88 − 150 − 161 = 1,401.26. Calories = 1,401.26 × 1.375 = 1,926.74. Fat = 100 − 50 − 20 = 30%. Protein = 1,926.74 × 0.20 ÷ 4 = 96.34 g; carbs = 1,926.74 × 0.50 ÷ 4 = 240.84 g; fat = 1,926.74 × 0.30 ÷ 9 = 64.22 g. All three shares are inside the adult ranges.

2,400 calories, 45% carbs, 30% protein. Fat = 25%. Protein = 2,400 × 0.30 ÷ 4 = 180 g; carbs = 2,400 × 0.45 ÷ 4 = 270 g; fat = 2,400 × 0.25 ÷ 9 = 66.67 g (600 calories from fat).

A low-carb split: 1,800 calories, 20% carbs, 35% protein. Fat = 45%. Protein = 1,800 × 0.35 ÷ 4 = 157.5 g; carbs = 1,800 × 0.20 ÷ 4 = 90 g; fat = 1,800 × 0.45 ÷ 9 = 90 g. Carbs (20%) are under the 45% to 65% range, and fat (45%) is over the 20% to 35% range.

A 35-year-old man, 5 ft 10 in (177.8 cm), 180 lb (81.647 kg), moderately active, losing 1 lb a week, 40% carbs and 30% protein. BMR = 816.47 + 1,111.25 − 175 + 5 = 1,757.72. TDEE = 1,757.72 × 1.55 = 2,724.46. Calories = 2,724.46 − 500 = 2,224.46. Protein = 2,224.46 × 0.30 ÷ 4 = 166.83 g; carbs = 2,224.46 × 0.40 ÷ 4 = 222.45 g; fat = 2,224.46 × 0.30 ÷ 9 = 74.15 g.

Other questions people ask

What are macros?

Macros (macronutrients) are the three nutrients that give most of the calories in food: protein, carbohydrate and fat. Protein and carbohydrate give 4 calories per gram, and fat gives 9. Counting macros means tracking grams of each, not only total calories.

How do I calculate my macros?

Multiply your daily calories by the share for each macro, then divide by its calories per gram. At 2,000 calories with 45% carbs, 30% protein and 25% fat: carbs are 2,000 × 0.45 ÷ 4 = 225 g, protein 2,000 × 0.30 ÷ 4 = 150 g, and fat 2,000 × 0.25 ÷ 9 = 56 g.

What is a good macro split?

For adults, the National Academies set Acceptable Macronutrient Distribution Ranges: 45% to 65% of calories from carbohydrate, 20% to 35% from fat and 10% to 35% from protein. The default here, 50% carbs, 20% protein and 30% fat, is inside all three. The calculator tells you when your split is outside a range.

What is the best macro split for weight loss?

Total calories matter most for weight loss. A higher protein intake can help keep muscle while you eat less (International Society of Sports Nutrition, 2017). Pick a loss goal to lower your calories, then choose a split you can keep to.

Why can I only set carbs and protein?

The three shares must add up to 100%, so fat gets whatever carbs and protein leave. If carbs and protein add up to more than 100%, there is no answer.

Where do the daily calories come from?

Choose "I know them" to type your own number. Otherwise the calculator estimates your total daily energy expenditure (TDEE) from your sex, age, height, weight and activity with the Mifflin-St Jeor equation, then adds or takes away calories for your goal: 500 fewer a day for about 1 pound a week of loss.