Use this calculator to estimate the protein intake per day you need to keep your weight stable, or to gain or lose weight, depending on your desired protein percentage as a part of your overall diet.
* where the calculator states "calories" it is actually "kCal", or kilocalories. Common usage, however, shortened "kilocalories" to "calories" so we are adhering to that convention.
How to use the protein calculator?
This protein calculator estimates your total daily energy expenditure (TDEE) and then calculates a percentage of it, depending on the selected protein percent of your total calorie intake.
To calculate your calorie needs, you have to enter age, gender, height, weight and activity level (includes exercise and other physical activity), which are all needed for the estimation. Finally, enter the percentage of total calories that you want to consume in proteins - you can check a list of proteins in common diets below. The tool will display the amount (in ounces or grams) and caloric equivalence of the proteins you need to eat per day.
What are proteins?
Proteins are one three main sources of daily energy supply (macronutrients): carbohydrates, proteins and fats. All of them are essential in maintaining a healthy life and good exercise condition, but different diets and different goals will call for a different percentage of proteins. Our protein calculator is here to help you estimate how much protein-rich food you need to eat to fulfill your diet plan.
A typical adult human body usually contains 10-12 kg (22 - 26.5 lb) of proteins, which has an energy equivalent of about 18-19,000 kCal. Most of it is located within skeletal muscle mass. Protein forms from amino acid building-block linkages with peptide bonds joining amino acids in chains, forming many diverse forms and chemical combinations: dipeptides, tripeptides, various polypeptides... Due to this variety, even one cell can contain thousands of different proteins, while a typical adult body contains approximately 50,000 different protein-containing molecules with differing biochemical functions.
While the body requires 20 amino acids, there are two major types: essential and non-essential. Essential amino acids are indispensable as they must be ingested through food. There are 8 such types of acids. The remaining 12 are non-essential amino acids. They can be synthesized from the body itself in normal quantities to support life. Please, note this doesn't mean non-essential amino acids are not important for the functioning of the body.
Unlike carbs and fats (lipids), proteins are not "stored" in reservoirs in the body, instead they are only found as tissue building blocks, plasma membranes and internal cellular material. Proteins are a key ingredient in maintaining and increasing muscle mass. Tissue synthesis (anabolism) accounts for more than 30% of protein intake early on in life, but the percentage declines with age. Amino acids degrade continually and adequate intake is still necessary for replacements, which is one more reason to use a protein calculator to estimate an adequate level of protein in your food regime.
Food sources of proteins
Dietary sources of complete proteins are mainly eggs, milk, meat, fish, and poultry. Eggs should be noted for providing the optimal mixture of essential amino acids. Here are the protein ratings of some common foods, reflecting how good of a source they are:
As you can see, both animals and plants produce proteins containing essential amino acids, but whereas animal sources usually provide a complete amino acids mix, individual vegetables usually offer only a limited set of amino acids, therefore food variety is more important when it comes to plant sources. There is no difference in the same amino acid, if it is derived from an animal or vegetable source. Reliance on animal sources for protein is associated with higher intake of cholesterol and fatty acids.
Despite being key for muscle building, simply eating a lot of protein will not automatically result in muscle gains, so don't opt for a diet with a very high protein percentage when using the protein calculator thinking that you will become the Hulk. In fact, proteins that are not immediately needed will be transformed or discarded. Consuming too much proteins is not harmless, too, as this would put a strain on your liver and kidneys, which will struggle to process and excrete the excess.
Proteins in common diets
Our protein calculator allows you to specify a custom percentage of proteins in your diet, but here we list six common diets: high & low carb, moderate, Zone, Keto and DASH, and their protein contents for your reference.
When considering your diet plan and protein percentage of the total calorie intake, don't forget to consult your physician if making significant changes relative to your current one.
How much protein do you need? Optimal protein intake
The generally recommended daily protein intake is 0.9 grams per kilogram of body weight for adolescents and 0.8 grams per kg of body weight for adults (~0.0145 oz per lb and ~0.013 oz per lb). You can use our protein requirement calculator to do the math for your weight with high accuracy. This is a minimum that you should not fall below, while the protein calculator here can estimate how much protein you will need to maintain a specific diet. If the recommendation produced is lower than the recommended minimum, then you may need to reconsider your diet, especially if you plan to adhere to it for a longer period of time.
A balanced approach would be to eat about 25% of your calories in the form of proteins. However, each person is different - with a specific health condition and fitness goals and your diet should be decided on accordingly, taking all factors into consideration.
Daily protein requirement for athletes
For building muscle mass and for maintaining muscle mass through a positive muscle protein balance, an overall daily protein intake in the range of 1.4–2.0 g protein/kg body weight/day (g/kg/d) is sufficient for most exercising individuals, according to a 2017 critical review  performed by the International Society of Sports Nutrition (ISSN). In the same statement they posit that "higher protein intakes (>3.0 g/kg/d) may have positive effects on body composition in resistance-trained individuals (i.e., promote loss of fat mass)". Additionally, the report suggests an optimal intake schedule of several doses of protein spread 3-4h apart evenly during the day.
While previously there were concerns related to too high doses of daily protein intake, current research proves the safety and efficacy of protein in general and whey protein in particular [2,3,4,5].
Promote muscle gain by increased protein intake
If you are an athlete, looking to increase your muscle mass, simply eating high-protein foods won't help. Dietary protein, after deamination, provides energy or recycles components of non-muscle molecules, or is converted to stored fat in fat depos. First of all, one needs adequate caloric intake corresponding to their exercise level. If the intake is insufficient during intense training even augmented protein intake may not be enough to maintain the proper balance of nitrogen since a disproportionate percentage of dietary protein will be catabolized to account for the energy deficit. So, you will burn your proteins before they can participate in muscle development.
However, there is some support that the now common practice of eating and drinking predigested protein in the form of shakes, powders, pills or bars might assist in muscle growth, especially whey protein. A 2019 meta analysis  supports the "efficacy and safety of whey protein supplements as an ergogenic aid on athletes' sports performance and recovery."
In most cases, the increased food intake needed to sustain an athletic, weight-lifting, resistance training or endurance training should be enough to maintain adequate protein levels in the body. The estimated requirement is for 1.4 - 2.0 grams per kg of body mass daily, which is usually accounted for in an adequate diet, but you can cross-check it with our protein requirement calculator by selecting a corresponding health condition, e.g. "intensive training". This may not be true if you are training hard while limiting your food intake in order to remain in a certain competition-level weight category (as in boxing, wrestling, etc.).
 Katch V.L., McArdle W.D., Katch F.I (2011) "Essentials of Exercise Physiology", fourth edition
 Jager, R. et. al. (2017) "International Society of Sports Nutrition Position Stand: Protein and exercise", Journal of the International Society of Sports Nutrition 14(20), DOI: 10.1186/s12970-017-0177-8
 Lam, F.C. et al. (2019) "Efficacy and Safety of Whey Protein Supplements on Vital Sign and Physical Performance Among Athletes: A Network Meta-Analysis", Frontiers in Pharmacology 10(317), DOI: 10.3389/fphar.2019.00317
 Van Elswyk, M. et al. (2018) "A Systematic Review of Renal Health in Healthy Individuals Associated with Protein Intake above the US Recommended Daily Allowance in Randomized Controlled Trials and Observational Studies", Advances in Nutrition 9(4):404-418, DOI: 10.1093/advances/nmy026
 WHO (2007) "Protein and Amino Acid Requirements in Human Nutrition", WHO Technical Report Series 935
Cite this calculator & page
If you'd like to cite this online calculator resource and information as provided on the page, you can use the following citation:
Georgiev G.Z., "Protein Calculator", [online] Available at: https://www.gigacalculator.com/calculators/protein-intake-calculator.php URL [Accessed Date: 27 Jan, 2021].