Macro Calculator | Calculate Your Daily Macros (Protein, Carbs, Fat)
Free macro calculator to estimate daily protein, carbs, and fat in grams. Enter calories and percentage split to see instant results. Uses USDA Atwater system.
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Understanding results
The calculator displays:
- Protein (g): Grams of protein per day
- Carbs (g): Grams of carbohydrates per day
- Fat (g): Grams of fat per day
- Calorie check: Total calories from the displayed grams (rounded; fat may be adjusted to match your target)
Results are rounded to whole numbers for practical meal planning.
Purpose
This macro calculator provides estimated macronutrient values based on your calorie target and preferred percentage split. The calculations use the Atwater system, the standard method established by the USDA for converting between calories and grams.
Enter your daily calorie target and adjust the percentage sliders to see suggested gram targets for protein, carbohydrates, and fat. These values are mathematical estimates based on the percentages you select.
How to use
- Enter your daily calories - Your target calorie intake
- Set your macro percentages - Must add up to 100%
- See your macros - Estimated grams of protein, carbs, and fat
Commonly Used Macro Splits
The following splits are frequently referenced in fitness and nutrition communities:
| Type | Protein | Carbs | Fat |
|---|---|---|---|
| Balanced | 30% | 40% | 30% |
| Higher Protein | 40% | 30% | 30% |
| Higher Carb | 30% | 50% | 20% |
| Low Carb | 40% | 20% | 40% |
| Very Low Carb | 20% | 5% | 75% |
Examples
Example 1: Higher Protein Split (2000 cal, 40/30/30)
Protein: (2000 × 0.40) ÷ 4 = 200g
Carbs: (2000 × 0.30) ÷ 4 = 150g
Fat: (2000 × 0.30) ÷ 9 = 67g
Example 2: Higher Carb Split (2500 cal, 30/50/20)
Protein: (2500 × 0.30) ÷ 4 = 188g
Carbs: (2500 × 0.50) ÷ 4 = 313g
Fat: (2500 × 0.20) ÷ 9 = 56g
Example 3: Very Low Carb Split (1800 cal, 20/5/75)
Protein: (1800 × 0.20) ÷ 4 = 90g
Carbs: (1800 × 0.05) ÷ 4 = 23g
Fat: (1800 × 0.75) ÷ 9 = 150g
How it works
Macro Calculation Formulas:
Protein (g) = (Calories × Protein%) ÷ 4
Carbs (g) = (Calories × Carbs%) ÷ 4
Fat (g) = (Calories × Fat%) ÷ 9
Why different divisors?
- Protein: 4 calories per gram
- Carbohydrates: 4 calories per gram
- Fat: 9 calories per gram
Example: 2000 calories, 30/40/30 split:
- Protein: (2000 × 0.30) ÷ 4 = 150g
- Carbs: (2000 × 0.40) ÷ 4 = 200g
- Fat: (2000 × 0.30) ÷ 9 = 67g
FAQ
How do I calculate my macros?
Multiply your daily calories by each macro percentage, then divide by calories per gram: protein and carbs ÷ 4, fat ÷ 9. Example: 2000 cal × 30% protein ÷ 4 = 150g protein.
What macro ratios are commonly used?
Common macro splits include 30/40/30 (protein/carbs/fat) for balanced intake, 40/30/30 for higher protein, and 30/50/20 for higher carbs. The right ratio depends on individual factors—consult a dietitian for personalized recommendations.
What macro splits do athletes commonly use?
Athletes often use higher carbohydrate splits like 30% protein, 50% carbs, 20% fat according to sports nutrition guidelines. Actual needs vary by sport, training intensity, and individual factors.
How many calories is 1 gram of protein?
1 gram of protein = 4 calories. This is why we divide by 4 when converting protein calories to grams.
How many calories is 1 gram of fat?
1 gram of fat = 9 calories. Fat is more calorie-dense than protein or carbs, which is why we divide by 9.
What is a typical keto macro split?
Ketogenic diets typically use approximately 20% protein, 5% carbs, 75% fat, which usually translates to under 20-50g of carbs per day. Keto diets should be undertaken with medical supervision.
Do macros need to add up to 100%?
Yes, your protein, carbs, and fat percentages should add up to 100% to account for all your calories.
What is IIFYM?
IIFYM (If It Fits Your Macros) is a flexible dieting approach where you can eat any foods as long as you hit your daily macro targets.
What are common protein intake references?
The FDA's Daily Value is 50g for a 2000-calorie diet. Sports nutrition organizations often reference 0.7-1g per pound of body weight for active individuals, but individual needs vary. Consult a healthcare provider for personalized recommendations.
What's the difference between tracking macros and calories?
Tracking calories measures total energy intake, while tracking macros breaks down the sources of those calories (protein, carbs, fat). Some people find tracking macros helpful for understanding their nutrition in more detail.
Methodology
How This Calculator Works
This calculator uses the Atwater system, the standard method for estimating caloric values of macronutrients:
Caloric Values (per USDA/FDA standards):
- 1 gram protein = 4 calories
- 1 gram carbohydrate = 4 calories
- 1 gram fat = 9 calories
These values are established by the USDA and used in FDA nutrition labeling.
Important Notice
This calculator provides mathematical estimates only based on the Atwater general factor system. The results are not personalized nutritional advice. Individual nutritional needs vary significantly based on age, sex, activity level, health conditions, and other factors. Consult a registered dietitian or healthcare provider for personalized dietary guidance.
Sources
Atwater Energy Values:
USDA: How Many Calories in a Gram of Fat, Carbohydrate, or Protein? - The USDA confirms the standard values: 4 kcal/g for protein and carbohydrates, 9 kcal/g for fat.
FDA Nutrition Labeling Guide - FDA uses the Atwater general factor system for nutrition labeling in the United States.
Atwater, W.O. & Woods, C.D. (1896). The Chemical Composition of American Food Materials. USDA Office of Experiment Stations, Bulletin 28 - The original research establishing caloric values for macronutrients.