Protein Intake Calculator

This protein intake calculator gives you a personalized, evidence-informed estimate of how much protein to eat each day. Instead of a single number, it shows a range — because protein needs genuinely vary from person to person — plus a practical daily target in the middle of that range. The estimate is based on your body weight, how physically active you are, and the goal you’re working toward, using ranges commonly cited in nutrition and sports-science research rather than an arbitrary formula.

How much protein do you need per day?

The baseline figure most people have heard of — about 0.8 grams of protein per kilogram of body weight per day — is the U.S. Recommended Dietary Allowance (RDA). It’s the amount needed to prevent deficiency in most healthy, sedentary adults, not necessarily the amount that supports muscle building, athletic performance, or active weight management. As activity level rises, or as a goal shifts toward building or preserving muscle, research generally supports higher intakes, often in the 1.2 to 2.2 g/kg/day range depending on the person and their training.

Age, activity level, and goals all shift where in that range a given person is likely to land, which is why this tool asks about each of them rather than applying one flat multiplier to everyone.

How the protein calculator works

The calculator converts your weight to kilograms (if you entered pounds) and matches your selected activity level and goal to a protein range expressed in grams per kilogram of body weight. It then multiplies that range by your weight to produce a low and high estimate in grams per day, and reports the midpoint as a practical daily target.

• Weight is the primary input, since protein needs scale with body size.
• Activity level shifts the range upward as training volume and intensity increase.
• Goal selects which evidence-based range applies (general health, muscle gain, fat loss, or endurance).
• Age is used only to apply a modest upward adjustment for adults 65 and older selecting the general-health goal, reflecting research on age-related protein needs (see Protein for Older Adults, below).
• Sex and height are collected for context but don’t change the protein figure itself, since the ranges used here aren’t sex-specific.

Unit conversion is handled automatically: entering weight in pounds converts internally at 1 lb = 0.453592 kg before any calculation happens, and height can be entered in centimeters or feet and inches.

Protein requirements by activity level

Physical activity increases the amount of protein your body uses for muscle repair, recovery, and adaptation, so recommendations climb accordingly:

• Sedentary: intakes near the baseline RDA (around 0.8 g/kg/day) are generally sufficient.
• Lightly to moderately active: modestly higher intakes support recovery from regular exercise.
• Very active: people training hard most days typically benefit from intakes well above the RDA.
• Athletes and extremely active individuals: sports-nutrition organizations commonly cite ranges up to roughly 2.0 g/kg/day for building or preserving lean mass, depending on the sport and training phase.

Protein for muscle gain

Resistance training creates a repeated stimulus for muscle protein synthesis, and adequate protein is what allows that stimulus to translate into muscle growth over time. The International Society of Sports Nutrition’s position stand on protein and exercise concludes that most exercising individuals do well with roughly 1.4–2.0 g/kg/day for building and maintaining muscle mass, with intakes toward the upper end typically favored by those doing serious strength or power training. Protein alone doesn’t build muscle — it works alongside a consistent resistance-training program and enough total energy intake.

Protein for weight loss

During a calorie deficit, higher protein intake helps preserve lean muscle mass that might otherwise be lost alongside fat, and protein tends to be more satiating than carbohydrate or fat, which can make a reduced-calorie diet easier to sustain. Research on hypocaloric dieting in resistance-trained individuals has pointed to ranges toward the higher end of typical recommendations to protect lean mass during weight loss. Protein is one supportive piece of a weight-management plan, not a substitute for an appropriate overall calorie balance, and it doesn’t directly “cause” fat loss on its own.

Protein for older adults

Aging is associated with changes in how the body processes protein, including a blunted muscle response to a given amount of dietary protein and an increased risk of age-related muscle loss (sarcopenia). A 2013 position paper from the PROT-AGE Study Group, an international group of researchers convened by the European Union Geriatric Medicine Society, recommends that healthy older adults (over 65) average at least 1.0–1.2 g/kg/day, with higher intakes advised for those who are physically active or managing acute or chronic illness. This calculator applies a modest upward shift for the general-health goal once age is set to 65 or older, reflecting that guidance.

How much protein should you eat per meal?

Research on muscle protein synthesis suggests it’s more effective to spread protein across the day than to concentrate it in one meal. A commonly cited practical target is roughly 20–40 grams of high-quality protein per meal (or about 0.25 g/kg of body weight), spaced every three to four hours, rather than saving most of your intake for a single large dinner. Distributing protein this way tends to make it easier to hit a daily target consistently, whatever that target turns out to be.

High-protein foods

A wide range of animal and plant foods can help meet your daily target. Actual protein content varies by serving size, cut, and preparation, so treat the examples below as a starting point rather than exact figures:

• Eggs
• Chicken breast and other poultry
• Fish and shellfish
• Greek yogurt
• Milk
• Cottage cheese
• Lentils
• Beans and other legumes
• Tofu and other soy foods
• Nuts and seeds

People eating primarily or entirely plant-based can meet their protein needs by combining a variety of these sources across the day, since together they supply the full range of essential amino acids.

Frequently asked questions

How much protein do I need per day?

It depends on your body weight, activity level, and goals, which is exactly what this calculator accounts for. As a general guide, sedentary adults often do well around 0.8 g/kg/day, while active adults or those focused on muscle gain or fat loss commonly benefit from roughly 1.2–2.2 g/kg/day.

Is 1 gram of protein per kg enough?

For many moderately active adults, around 1 g/kg/day sits comfortably within a reasonable range, though it may be on the low side for people doing significant resistance training or trying to preserve muscle during weight loss, and on the high side for a fully sedentary adult whose needs are closer to the 0.8 g/kg RDA.

How much protein do I need to build muscle?

Sports-nutrition research generally points to roughly 1.4–2.0 g/kg/day for building and maintaining muscle mass in people doing regular resistance training, with intakes toward the upper end more common among dedicated strength athletes.

Should I eat more protein when trying to lose weight?

Many people benefit from higher protein intake during a calorie deficit, since it helps protect lean muscle mass and supports satiety. It’s not a guarantee of fat loss by itself — overall calorie balance is still the main driver of weight change.

Does age affect protein requirements?

Yes. Research suggests older adults often need more protein than younger adults to counter age-related changes in protein metabolism and to help maintain muscle and function, which is reflected in this calculator’s adjustment for ages 65 and up.

Can I get enough protein from plant foods?

Yes. A varied plant-based diet that includes legumes, soy foods, whole grains, nuts, and seeds can supply all essential amino acids and meet typical daily protein targets.

Is too much protein harmful?

For most healthy adults, protein intake within the commonly studied ranges (up to roughly 2–2.2 g/kg/day) hasn’t been shown to cause kidney or bone harm. People with existing kidney disease or other conditions affecting protein metabolism should follow individualized guidance from their healthcare provider, since their needs can be very different.

Should protein intake be based on body weight?

Body weight is the standard basis used in dietary reference values and sports-nutrition guidelines because protein needs scale fairly closely with lean body mass and overall size, which is why this calculator (and most evidence-based recommendations) expresses protein needs in grams per kilogram of body weight.

Medical disclaimer

Sources & references

• Institute of Medicine (National Academies). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005). nap.nationalacademies.org/read/10490
• Jäger R, et al. “International Society of Sports Nutrition Position Stand: protein and exercise.” Journal of the International Society of Sports Nutrition, 2017. jissn.biomedcentral.com
• Bauer J, et al. “Evidence-Based Recommendations for Optimal Dietary Protein Intake in Older People: A Position Paper From the PROT-AGE Study Group.” Journal of the American Medical Directors Association, 2013. doi.org/10.1016/j.jamda.2013.05.021
• U.S. Department of Agriculture & Department of Health and Human Services. Dietary Guidelines for Americans. dietaryguidelines.gov
• Academy of Nutrition and Dietetics. eatright.org