Protein Intake Calculator
Estimate your daily protein target in grams from body weight and an evidence-based goal factor (g of protein per kg of body weight).
How to use this tool
- Enter your body weight in kilograms.
- Select the goal that matches your activity and aims.
- Read your daily protein target in grams.
- Use the table to compare goals at your weight.
The protein intake calculator estimates how many grams of protein to aim for each day, based on your body weight and whether your goal is basic health, general fitness, or building muscle.
Formula
Daily protein (g) = body weight (kg) × factor (g/kg)
The factor reflects the goal: about 0.8 g/kg for the sedentary RDA, 1.2 g/kg for general activity, 1.6 g/kg for building muscle, and up to roughly 2.2 g/kg at the upper sports range.
How it works
Protein needs scale with body weight, so dietary guidance is usually given as grams of protein per kilogram of body weight per day. The Recommended Dietary Allowance for sedentary adults is about 0.8 g/kg, which is set to prevent deficiency rather than to optimise training. Active people, older adults, and those building muscle generally benefit from more, commonly in the 1.2–2.2 g/kg range reported in sports-nutrition reviews.
This calculator multiplies your weight by the factor for your selected goal. It uses total body weight, which can overestimate needs at very high body-fat levels, where some practitioners use lean or adjusted weight instead. Protein needs also change with pregnancy, kidney disease, and illness.
This calculator is provided for general information and education only and is not medical advice. Clinical formulas are screening and estimation tools, not diagnoses, and they assume valid, correctly-measured inputs. Always consult a qualified clinician before making any decision about your health.
Worked example
70 kg adult building muscle (1.6 g/kg)
- Choose the goal factor: building muscle = 1.6 g/kg
- Multiply by body weight: 70 × 1.6 = 112 g
- Round to two decimals = 112.00 g per day
Daily protein target = 112.00 g/day (1.60 g/kg)
Daily protein target by goal (grams per day)
| Goal (g/kg) | 60 kg | 70 kg | 80 kg | 90 kg |
|---|---|---|---|---|
| Sedentary RDA (0.8) | 48.00 | 56.00 | 64.00 | 72.00 |
| Active (1.2) | 72.00 | 84.00 | 96.00 | 108.00 |
| Building muscle (1.6) | 96.00 | 112.00 | 128.00 | 144.00 |
| Upper sports (2.2) | 132.00 | 154.00 | 176.00 | 198.00 |
Key terms
- RDA
- Recommended Dietary Allowance — the intake judged sufficient for most healthy people; for protein it is about 0.8 g/kg/day.
- g/kg
- Grams of protein per kilogram of body weight, the standard way protein targets are expressed.
- Protein factor
- The g/kg multiplier chosen for a goal, from 0.8 (RDA) up to about 2.2 (upper athletic range).
- Nitrogen balance
- The difference between protein intake and protein breakdown; positive balance supports building or maintaining muscle.
Frequently asked questions
- How much protein do I need per day?
- It depends on your goal. Sedentary adults need about 0.8 g/kg, active people around 1.2 g/kg, and those building muscle often aim for 1.6–2.2 g/kg of body weight per day.
- Should I use total or lean body weight?
- This tool uses total body weight, which is fine for most people. At very high body-fat levels, basing the target on lean or adjusted weight avoids overestimating needs.
- Can I eat too much protein?
- Very high intakes are unnecessary for most people and may strain the kidneys of those with existing kidney disease. Anyone with kidney problems should get individual advice.