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- A healthy adult needs at least 0.8 g of protein per kg of body weight a day, which is about 0.36 g per lb.
- People who exercise, lift weights, are over 65 or are cutting fat often aim higher, between about 1.0 and 2.4 g per kg.
- The calculator gives a daily range in grams, a split across 3 or 4 meals and the calories that protein supplies.
- This is general information, not medical advice.
How to use the protein intake calculator
Choose pounds or kilograms
Pick the unit you know your weight in. The calculator converts it for you.
Enter your body weight
Use your current weight. The calculator is for adults.
Pick your situation
Choose general health, adults 65 and over, regular exercise, building muscle, or losing fat while keeping muscle.
Read your range
You get a daily range in grams, the amount per meal for 3 or 4 meals, and the calories from protein.
How daily protein is calculated
Protein targets are set per kilogram of body weight, so a larger person needs more protein than a smaller one. The calculator multiplies your weight by a low and a high figure for your situation.
The formula
Daily protein (g) = body weight (kg) × grams per kg
Body weight (kg) = pounds × 0.4536
Calories from protein = grams × 4
Each gram of protein supplies about 4 calories.
Grams per kg by situation
General health (healthy adult): 0.8 g/kg
Adults 65 and over: 1.0 to 1.2 g/kg
Regular exercise: 1.2 to 1.6 g/kg
Building muscle: 1.6 to 2.2 g/kg
Losing fat and keeping muscle: 1.6 to 2.4 g/kg
The 0.8 g/kg figure is the US Recommended Dietary Allowance for healthy adults. The higher ranges follow figures commonly used in sports nutrition and ageing research.
Worked examples
A regularly active adult
Someone weighs 154 lb (about 70 kg), exercises a few times a week and picks Regular exercise (1.2 to 1.6 g/kg).
A daily target of 84 to 112 g is a range, not a number to hit exactly every day.
Someone lifting weights
A person who weighs 180 lb (about 82 kg) trains with weights and picks Building muscle (1.6 to 2.2 g/kg).
Most studies show the extra benefit levels off near the lower part of this range, so the low end is a sound starting point.
Protein in common foods
Rough protein per serving
Amounts vary by brand and preparation, so check the label when you can.
Protein powders and bars count toward your total too.
Who a protein calculator helps
Strength training and sport
Match your daily protein to your training so recovery and muscle growth are not held back by your diet.
Healthy ageing
Adults over 65 tend to need more protein per kilogram to help keep muscle and strength.
Weight loss
A higher protein intake helps many people feel full and protects muscle while eating fewer calories.
Plant-based eating
See how many grams to plan for, then build meals from beans, lentils, tofu, grains and nuts.
Children, pregnant or breastfeeding women, and people with kidney disease or other medical conditions can have different protein needs. Ask a doctor or a registered dietitian before you change how much protein you eat.
Protein intake calculator FAQ
How much protein do I need per day?
A healthy adult needs at least 0.8 g per kg of body weight, about 0.36 g per lb. For a 154 lb (70 kg) adult that is 56 g a day. People who exercise regularly, lift weights or are over 65 are often advised to eat more.
Is more protein always better?
No. For building muscle, gains tend to level off around 1.6 g per kg in most studies, and eating well above that rarely adds much. People with kidney disease may need to limit protein, so check with a doctor first.
Should I use my current weight or my goal weight?
This calculator uses your current weight. Some dietitians use a healthy or goal weight for people with a lot of excess body fat, so ask a professional if that applies to you.
How should I spread protein across the day?
Total daily protein matters most. Spreading it over three or four meals is a practical habit, and the calculator shows the amount per meal for both.
Can I get enough protein on a plant-based diet?
Yes. Beans, lentils, soy foods, whole grains, nuts and seeds all provide protein. Some people on plant-based diets aim for the upper part of their range because plant proteins can be slightly less digestible.
Do supplements count toward the total?
Yes. Protein from powders, bars and drinks counts the same as protein from food. Add up all sources over the day.