How to Calculate Your Protein Intake in Three Steps

To calculate protein intake, multiply your body weight in kilograms by 1.2 for the low end and by 1.6 for the high end. A 70 kg adult gets 84–112 g a day. In pounds, use 0.55 and 0.73 g per lb. The range comes from the 2025–2030 Dietary Guidelines for Americans, and the 0.8 g/kg minimum is only a floor.

How do I calculate how much protein I need?

Three steps. Convert pounds to kilograms by dividing by 2.2. Multiply by 1.2 and by 1.6. That’s your daily range in grams. Then adjust it to your calorie needs, which the Dietary Guidelines make a condition. At 150 lb that’s 150 ÷ 2.2 = 68.2 kg, then 68.2 × 1.2 = 82 g and 68.2 × 1.6 = 109 g.

I worked four body weights in pounds so you can find your row without a calculator. The minimum column uses 0.8 g/kg for comparison.

Body weight	In kilograms	Minimum (0.8 g/kg)	Low end (1.2 g/kg)	High end (1.6 g/kg)
120 lb	54.5 kg	44 g	65 g	87 g
150 lb	68.2 kg	55 g	82 g	109 g
180 lb	81.8 kg	65 g	98 g	131 g
210 lb	95.5 kg	76 g	115 g	153 g

Between rows? Multiply by the per-pound figures instead: 165 lb × 0.55 is 91 g, and 165 lb × 0.73 is 120 g. Which end you aim for is up to you. I stay near the low end when I eat to maintain my weight, and I move up when I train hard, and how much protein to build muscle covers what people who lift need. That is just my habit, and the Guidelines don’t ask for it.

The Guidelines hand you two ends of a range, and how much protein you should eat a day explains how it is built. At 70 kg the two ends sit 28 g apart, which is the protein in about 87 g of braised chicken breast at 32.1 g per 100 g. That gap is smaller than one lunch.

Which weight should I use to calculate protein intake?

Your actual weight, up to a point. The Guidelines say “body weight” and don’t say which one, and a high scale weight can inflate the result. I cap the weight I plug in at the one that gives a BMI of 25 for your height, the top of the usual range of 18.5 to 24.9. Below that cap I use the scale number as it is. No published equation backs this, and I do it only so that a high scale weight can’t inflate the target.

Take someone 175 cm tall who weighs 120 kg. A BMI of 25 at 1.75 m is 25 × 1.75 × 1.75, or 76.6 kg. That gives 92 g a day at 1.2 g/kg and 123 g at 1.6 g/kg. With 120 kg you’d get 144–192 g, 56% more.

The protein calculator does this arithmetic for you and never goes below 60 g.

How do I calculate protein as a percent of calories?

Grams times 4, divided by your calories. Protein has 4 kcal per gram under the general Atwater factors, so 112 g is 448 kcal: 22% of a 2,000 kcal day, 28% of a 1,600 kcal day. Both sit inside protein’s Acceptable Macronutrient Distribution Range of 10–35% of calories. To go from a percentage to grams, multiply calories by the percentage and divide by 4: 20% of 2,000 kcal is 400 kcal, or 100 g.

The 4 is an average. FAO lists specific factors from 2.44 kcal/g for some vegetable proteins to 4.36 kcal/g for eggs. A mostly plant-based day can land below the percentage you calculate.

How do I calculate the protein in what I eat?

Use one formula: protein per 100 g, times grams, divided by 100. A 156 g container of plain nonfat Greek yogurt has 10.3 g of protein per 100 g, so 10.3 × 1.56 is 16.1 g. Every row below works the same way, with the USDA FoodData Central record linked in the first column. The grams come from the portion weights printed in those records (50 g for a large egg, 107 g for a drained can of tuna, 155 g for a cup of edamame, 29 g for a slice of bread), except the cottage cheese, which I set at 150 g.

Food	Grams	Protein per 100 g	Protein
Wheat bread, 2 slices	58 g	10.67 g	6.2 g
Hard-boiled egg, 1 large	50 g	12.58 g	6.3 g
Light tuna in water, drained, 1 can	107 g	19.0 g	20.3 g
Edamame, frozen, prepared, 1 cup	155 g	11.91 g	18.5 g
Greek yogurt, plain, nonfat, 1 container	156 g	10.3 g	16.1 g
Lowfat cottage cheese	150 g	11.0 g	16.5 g
Day total			83.9 g

That’s 83.9 g, inside the 82–109 g range of the 150 lb row. State matters. Raw chicken breast has 22.5 g of protein per 100 g, and the braised breast from the first section has 32.1 g. So 100 g weighed raw and 100 g weighed cooked are two different entries. Pick the record that matches how the food sits on your scale, and weigh in grams, not cups.

How precise can a protein target be?

Less than the single numbers suggest. The 0.8 g/kg minimum comes from nitrogen-balance studies. A 2017 review in Advances in Nutrition notes that a different statistical treatment of the same data gives an average requirement of 0.93 g/kg and an RDA of 1.2 g/kg, about 50% above the official ones.

This guide is for healthy adults. Kidney disease, pregnancy and breastfeeding all change the math, so a doctor should set the number in those cases. Under 18 the calculation is different again. Past 65 the experts have their own minimums, and aging and protein intake covers what the research says.

Log three ordinary days and compare the average with your range. Under the low end by more than a fifth? Add a protein serving to the biggest gap. Whether a shortfall shows up in your body is a separate question, answered in signs of low protein intake.

Calsa shows protein with calories as you log, and each entry shows where its calories come from and the math, per 100 g × grams.