Protein Calculator

Many of us are unsure about the amount of protein we should include in our diets. Using your age, weight, height, sex, and level of physical activity, our protein calculator will help you find out your protein needs.

Our easy-to-use calculator involves just five simple stages. First, choose whether you would like to fill in your details using imperial or metric measurements. Then, enter your sex and your age in years. Next, enter your height and weight. Following this, pick your activity level out of low, medium, high or intense or select custom to enter the activity multiplier manually. Finally, get your results by clicking on "Calculate".

Protein Intake Calculator


Understanding protein

A macronutrient, protein can be found in all plant and animal foods. Protein enables the body to maintain and repair skill cells, preserve lean muscle mass and build tissue. Protein should provide some of your daily intake of calories but exactly how much can be a challenge to figure out.

How our protein calculator determines your protein needs

Our protein calculator works uses a range of formulas to provide you with your recommended protein intake.

Imagine that Mary needs to figure out how much protein she should be consuming. Mary is female, 25, 145 pounds and 5’8”. To start, it is necessary to determine her recommended daily intake of calories, which is achieved using Mary's BMR. Using the Harris-Benedict formula, BMR is calculated as follows (where measurements are given in metric, and W is weight, H is height and A is age in years):

For women: 655.1 + 9.563(W) + 1.85(H) - 4.676(A) = BMR
For men: 66.5 + 13.75(W) + 5.003(H) - 6.775(A) = BMR

So, Mary's weight of 145 pounds becomes 65.9 kg (2.2 pounds = 1 kg), her height of 5’8”, or 68 inches, becomes 173 cm (1 inch = 2.54 cm) and her BMR is then calculated as follows:

BMR = 655.1 + [(9.563)*(65.9 kg)] + [(1.85)*(173 cm)] - [(4.676)*(25 years)]

BMR = 655.1 + 630.2 + 320 – 116.9 = 1,488 calories

Mary is also active and exercises regularly. So, her BMR will need to be multiplied by from 1.2 to 1.9 as she will need more calories as an active person. Assuming Mary does a mid-level amount of exercise, her calorie intake is multiplied by 1.55:

1,488 x 1.55 = 2,306 calories per day

Having determined Mary's recommended daily calorie intake, we can now figure out how much protein she needs.

Our calculator provides two recommendations.

The first recommendation is determined according to guidance provided by the CDC, the Centers for Disease Control and Prevention, which advises that adults get 10% to 35% of their daily calories from protein.

So, Mary's requirements will be as a minimum (10%): (2,306 x 0.1) / 4 = 57 g

And, as a maximum (35%): (2,306 x 0.35) / 4 = 201 g

This means that Mary needs to consume from 57 g to 201 g of protein every day.

The second recommendation is determined according to guidance provided by the ADA, the American Dietetic Association, which states that a healthy adult should consume from 0.8 g to 1.0 g of protein per kg of their body weight.

So, Mary's needs can be calculated as follows:

Minimum requirements: 65.9 kg (0.8 g/kg) = 52 g

Maximum requirements: 65.9 kg (1.0 g/kg) = 65 g

Thus, according to the ADA, Mary needs to consume from 52 g to 65 g of protein daily.


1. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. The National Academies Press, Washington, DC, 2005.

2. Manual of Clinical Dietetics, 6th ed. Chicago, Ill: American Dietetic Association; 2000

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