Macro Calculator

How to use this calculator

Choose how to set your calories:

• I know my calories: type in your daily target, for example from the calorie calculator.
• Calculate it for me: enter your sex, age, height, activity level and goal, and the calculator estimates your target from your maintenance calories (the same method as the TDEE calculator).

Either way, enter your weight so the calculator can express protein per kilogram. Then pick a diet: balanced, low-carb, high-protein, keto, or custom percentages. You’ll see:

• daily grams of protein, carbs and fat, with the calories and share for each
• protein per kilogram of body weight, and the range from the Dietary Guidelines for your weight
• limits and targets for saturated fat and fiber
• a table of grams per meal for 3, 4 or 5 meals

The formula

Each macronutrient gets a share of your calories, and each has a fixed energy value per gram (the Atwater factors): 4 calories per gram for protein and carbohydrate, 9 per gram for fat.

Per-meal amounts are the daily grams divided by the number of meals.

Worked example

Take 2,000 calories a day on the balanced split (20% protein, 50% carbs, 30% fat) for someone who weighs 160 lb (72.6 kg):

1. Protein: 2,000 × 20% ÷ 4 = 100 g
2. Carbs: 2,000 × 50% ÷ 4 = 250 g
3. Fat: 2,000 × 30% ÷ 9 = 67 g

Spread over four meals, that’s about 25 g of protein, 63 g of carbs and 17 g of fat per meal. The protein works out to 1.38 g per kg of body weight, inside the Dietary Guidelines’ 1.2 to 1.6 g/kg range (87 to 116 g for this person). The calculator also shows a saturated fat ceiling of 22 g (10% of calories) and a fiber goal of 28 g (14 g per 1,000 calories).

Macros by diet and calorie level

Grams per day for each preset, rounded to the nearest gram:

The balanced preset sits inside the Acceptable Macronutrient Distribution Ranges set by the National Academies for adults: 10% to 35% of calories from protein, 45% to 65% from carbohydrate and 20% to 35% from fat. The other presets deliberately step outside those ranges for carbs or fat. That’s a common choice, but it’s worth knowing.

How much protein you need

Protein needs are best set by body weight rather than as a percentage, because a fixed percentage gives a small person on a low calorie budget too little and a large person on a high one more than they need. Commonly cited ranges:

• 0.8 g/kg: the Recommended Dietary Allowance for adults, enough to meet the needs of nearly all healthy people.
• 1.2–1.6 g/kg: the protein goal in the Dietary Guidelines for Americans, 2025–2030, adjusted to your calorie needs.
• 1.4–2.0 g/kg: the International Society of Sports Nutrition’s range for most people who exercise regularly.

Higher protein intakes are especially useful when you’re eating in a deficit, because they help preserve muscle. If your protein comes out low, choose the high-protein preset or set custom percentages. The calculator warns you if you fall below 0.8 g/kg. People with kidney disease should ask their doctor before raising protein.

Choosing a split

• Balanced suits most people and is the easiest to build from everyday foods.
• Low-carb and keto can help some people control appetite, but they make fiber harder to reach and need careful planning. If you have diabetes or kidney disease or take medication for blood sugar or blood pressure, check with your doctor before cutting carbs sharply.
• High-protein is a good fit when you’re losing weight or strength training.
• Custom lets you enter any percentages that add up to 100%.

Whichever split you choose, the Dietary Guidelines advise keeping saturated fat under 10% of daily calories, and the National Academies’ fiber goal is 14 g per 1,000 calories.

Assumptions and limitations

• The Atwater factors (4, 4 and 9) are averages. Food labels and real foods vary a little.
• Alcohol provides 7 calories per gram and isn’t included in any macro.
• Your calorie target is the biggest driver of results. If you calculate it here, it’s an estimate from the Mifflin-St Jeor equation and an activity factor.
• These targets are for healthy adults, not for pregnancy, breastfeeding, children or medical diets.

Sources

• U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2025–2030 (protein goal of 1.2–1.6 g/kg; saturated fat under 10% of calories). See also RealFood.gov.
• Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press, 2005 (RDA, AMDRs, fiber).
• Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
• Mifflin MD, St Jeor ST, Hill LA, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241–247.

This calculator gives general estimates for healthy adults and isn’t medical or dietary advice. If you have a health condition, talk to your doctor or a registered dietitian before changing your diet.

Updated November 2026. Results are estimates for educational purposes and depend on the inputs you provide.