Protein Calculator
Calculate your daily protein intake in grams based on scientific sports nutrition guidelines for muscle building, fat loss cutting, or maintenance.
| Common Food Source | Serving Size | Approx. Protein |
|---|---|---|
| Chicken Breast (Cooked) | 100g (3.5 oz) | 31 g |
| Whey Protein Powder | 1 Scoop (30g) | 24 g |
| Greek Yogurt (Non-fat) | 1 Cup (227g) | 20 g |
| Whole Large Eggs | 2 Large Eggs | 12 g |
| Firm Tofu | 100g (3.5 oz) | 10 g |
How to Use This Calculator
- Select Your Unit System: Toggle between Imperial (pounds) or Metric (kilograms) depending on your scale.
- Input Body Weight & Goal: Select whether you are actively building muscle, cutting body fat while sparing muscle, maintaining weight, or looking for minimum sedentary health intake.
- Choose Meal Frequency: Distribute your daily requirement evenly across 3 to 6 meals to hit optimal muscle protein synthesis pulses.
- Review Your Daily & Per-Meal Targets: Use the built-in food equivalents table to build your daily grocery and meal plan.
The Formula
Sports science nutrition computes protein intake based on body weight adjusted for metabolic demand and physical activity:
Standard multipliers validated across sports nutrition literature:
- Sedentary RDA: 0.36 g/lb (0.8 g/kg) — Baseline to prevent physiological deficiency.
- Endurance & Active Maintenance: 0.65 to 0.75 g/lb (1.4 to 1.6 g/kg) — Supports glycogen synthesis and muscle repair.
- Muscle Gain / Bodybuilding: 0.82 to 1.0 g/lb (1.8 to 2.2 g/kg) — Maximizes muscle hypertrophy under heavy lifting stimulus.
- Fat Loss / Aggressive Cutting: 0.95 to 1.1 g/lb (2.1 to 2.4 g/kg) — Satiety and lean tissue preservation in a deficit.
Each gram of dietary protein provides approximately 4 kilocalories of biological energy.
Worked Example
Scenario Profile
A 180 lb (81.6 kg) lifter engaging in resistance training 4 days per week aiming for clean muscle gain with 4 meals daily:
1. Target Ratio: 1.0 gram per pound of body weight.
2. Daily Protein Target: 180 lbs × 1.0 g/lb = 180 grams / day.
3. Per Meal Distribution: 180 g ÷ 4 meals = 45 grams per meal.
4. Caloric Energy: 180 g × 4 kcal/g = 720 kcal from dietary protein.