About the Protein Calculator
A protein calculator sets a daily protein target from your body weight and activity level. Protein is the macronutrient most consistently under-consumed relative to need, and it is the one that most directly determines whether you keep muscle while losing fat.
The formula
Daily protein (g) = body weight (kg) · activity multiplierMultipliers run from roughly 0.8 g/kg for sedentary adults through 1.2 to 1.6 for active people, 1.6 to 2.0 for athletes, and up to 2.2 g/kg for those building muscle in a deficit.
How to use this calculator
- 1Enter your Body Weight (kg). The field starts at
75, which you can overwrite. - 2Enter your Activity Level (1=Sedentary, 2=Active, 3=Athlete, 4=Bodybuilder). The field starts at
2, which you can overwrite. - 3Read the result straight away — it recalculates as you type, so there is no button to press. Use Share to copy a link that reopens the page with your exact numbers filled in.
Worked example
| Input | Value |
|---|---|
| Body Weight (kg) | 75 |
| Activity Level (1=Sedentary, 2=Active, 3=Athlete, 4=Bodybuilder) | 2 |
Result
Activity: Active
Protein Range: 90–120 g/day
Per kg: 1.2–1.6 g/kg
Calories from Protein: ~420 kcal/day
Those are the values the page loads with, so you can reproduce this result yourself and then change one field at a time to see what drives the outcome.
Understanding your result
The widely cited 0.8 g per kg figure is a minimum to prevent deficiency in sedentary adults, not an optimum. Research on resistance-trained populations consistently supports 1.6 to 2.2 g per kg for muscle retention and growth, with little additional benefit above that in most studies.
Protein also has the highest thermic effect of the three macronutrients — roughly 20 to 30 percent of its calories are used in digestion, against 5 to 10 percent for carbohydrate and fat. Combined with its strong effect on satiety, this is why higher-protein diets make calorie deficits easier to sustain.
Things worth knowing
- Spread intake across three or four meals of 25 to 40 g. Muscle protein synthesis responds better to distribution than to one large serving.
- Complete proteins — meat, fish, eggs, dairy, soy, quinoa — contain all nine essential amino acids. Plant sources are best combined.
- Leucine is the key trigger for muscle protein synthesis, and roughly 2.5 to 3 g per meal is the usual target.
- Higher protein is safe for healthy kidneys. Existing kidney disease requires medical guidance on intake.
- Older adults need more, not less — around 1.2 to 1.6 g per kg — to counter age-related muscle loss.
Frequently asked questions
How much protein do I need per day?+
0.8 g per kg is the minimum to avoid deficiency. Active people need 1.2 to 1.6, and those training seriously or dieting benefit from 1.6 to 2.2 g per kg of body weight.
Can too much protein damage my kidneys?+
Not in people with healthy kidneys — high-protein intakes have been studied extensively without evidence of harm. Those with existing kidney disease do need medically supervised limits.
Is protein timing important?+
Distribution across the day matters more than the post-workout window. Three or four servings of 25 to 40 g support muscle protein synthesis better than the same total in one meal.
Can I meet protein needs on a plant-based diet?+
Yes, though it takes more planning. Combine legumes, grains, soy, nuts, and seeds to cover all essential amino acids, and aim slightly higher in total since plant proteins are somewhat less digestible.