Protein Grams from Calories
Grams of protein for a target protein ratio of the diet.
Formula
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Example
0.30 × 2000 / 4 ⇒ 150 g
How it works
This formula converts a planned share of daily calories into the equivalent grams of protein. It works because protein provides about 4 calories per gram, so you first find how many calories should come from protein, then divide by 4 to turn those calories into grams.
When to use it
Use this when planning macros for a diet, meal plan, or sports nutrition target and you know the desired protein percentage of total calories. It is also useful for checking whether a food plan matches a target protein intake.
Worked example, step by step
Target protein fraction r = 0.25 Daily calories C = 2400 Step 1: Multiply the protein fraction by calories: 0.25 × 2400 = 600 protein calories Step 2: Convert protein calories to grams: 600 ÷ 4 = 150 g Answer: 150 g of protein per day
Common mistakes to avoid
- Using 4 calories per gram for fat or carbohydrates instead of only protein
- Forgetting to convert the protein fraction from a percentage to a decimal, such as using 25 instead of 0.25
- Dividing the total daily calories by 4 without first applying the protein fraction
Did You Know?
Because protein is 4 kcal/g, a 2000-kcal "30% protein" plan works out to a very achievable 150 g a day.
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