Protein Calculator
See how much protein a day three major health bodies would put you on, from your age, size and how much you move. They disagree with each other, which is the useful part — the spread between them is the range worth aiming inside.
BMR estimation formula
What each institution recommends:
The CDC figures come from your calorie needs, so they move with activity. The other two come from body weight alone.
| Food | Protein |
|---|---|
| Chicken breast, 100 g | 31 g |
| Greek yogurt, 170 g pot | 17 g |
| Lentils, 1 cup cooked | 18 g |
| Egg, 1 large | 6 g |
| Tinned tuna, 1 tin | 25 g |
| Firm tofu, 100 g | 17 g |
| Milk, 1 cup | 8 g |
| Peanut butter, 2 tbsp | 7 g |
Figures vary by brand and cut. Spreading protein across meals is easier than meeting a target in one sitting.
Why three answers instead of one
Most calculators hand you a single protein number. This one gives three, because three respected bodies genuinely disagree, and hiding that behind an average would make the result look more certain than the science is.
They disagree because they are answering different questions. The World Health Organization figure is a public-health floor: the amount below which deficiency becomes likely across a population. The American Dietetic Association range is about supporting training and body composition. The CDC band is not about protein at all in isolation — it is a share of your total calories, sitting alongside carbohydrate and fat.
So the right way to read the result is not to pick a winner. It is to notice that the floor sits well below the training range, and to place yourself between them based on what you are actually doing.
Where each number comes from
Two of the three depend only on your body weight. The third depends on how much you move, which is why it swings the most when you change the activity setting.
0.83 g per kg of body weight
ADA range
sedentary 0.8 to 1.0 g per kg
otherwise 1.0 to 1.8 g per kg
CDC range — 10 to 35% of daily calories
BMR × activity = daily calories
grams = calories × 10% (and 35%) ÷ 4.1
Worked through for 78 kg, 176 cm, 32, male, light activity
BMR = (10 × 78) + (6.25 × 176) − (5 × 32) + 5 = 1725 kcal
daily calories = 1725 × 1.375 = 2372 kcal
WHO = 65 g · ADA = 78 to 140 g · CDC = 58 to 203 g
The 4.1 in that last line is protein's energy density — a gram of protein releases about four kilocalories, and 4.1 is the figure the underlying convention uses. It matters because the whole CDC band is a calorie share converted into grams, so the constant sets the scale of both ends.
Notice that the ADA range steps rather than slides. Move from sedentary to light activity and it jumps from 0.8–1.0 to 1.0–1.8 g per kg, then stays there no matter how much further you push the activity setting. Only the CDC figures keep climbing, because only they are tied to calories.
The floor is not the target
The single most misread number in nutrition is 0.8 g per kg, usually quoted as "the recommended amount". It is not a recommendation to aim for. It is the point below which a population starts showing deficiency — the bottom of the safe range, set to cover almost everybody's minimum need.
Eating at the floor is not dangerous, and for a sedentary adult it is genuinely adequate. But it is the nutritional equivalent of the minimum wage: sufficient, not optimal, and set for the least demanding case rather than yours. Anyone lifting, running, dieting, recovering from injury, or simply getting older has reasons to sit higher.
Older adults are the clearest example. Muscle becomes less responsive to protein with age, so the same intake does less work, and most current guidance suggests people over about sixty-five do better nearer 1.0 to 1.2 g per kg than at the floor. The floor was never calculated with them in mind.
Reading the spread
Look at your own three results and the gap between the lowest and highest is usually enormous — often a factor of three. That is not the calculator hedging. It is a real reflection of how wide the sensible range is.
A useful way to place yourself inside it: if you are not training, the WHO figure to the bottom of the ADA range covers you comfortably. If you train a few times a week, the middle of the ADA range is a reasonable target. If you are lifting seriously or eating at a deficit, the top of the ADA range is where most evidence points.
The top of the CDC band is worth treating with suspicion as a target. Thirty-five percent of calories from protein is an unusual way to eat, and the band exists to describe an acceptable distribution of macronutrients rather than to recommend its own upper edge. Almost nobody needs to be up there.
Spreading it across the day
A daily total is the number this page produces, but the body does not work in daily totals. Muscle protein synthesis responds to individual meals, and there is a limit to how much a single sitting can put to that use — roughly 25 to 40 grams for most adults, depending on body size.
Eat 120 grams as one large dinner and a good part of it is simply used for energy rather than repair. Split the same 120 across three or four meals and more of it lands where you wanted it. The practical version of this is unglamorous: get some protein into breakfast, which is the meal most people skip it at entirely.
The other consideration is source. Animal proteins, soy and quinoa contain all nine essential amino acids in useful amounts. Most plant sources are short of one or another, which is not a problem across a varied day — the old advice about carefully combining foods at each meal has not held up — but it does mean a plant-based diet benefits from variety rather than leaning on a single staple.
Whether more is better
Up to a point, yes. Past that point, the evidence goes flat rather than negative.
For building or holding muscle, the returns taper off somewhere around 1.6 g per kg for most people, with a little more offering a little more for some. Going far beyond that is not harmful in a healthy adult, but it is not doing much either, and every gram of protein is a gram not spent on carbohydrate or fat, which have their own jobs.
Protein does have one advantage worth knowing about if you are trying to lose weight: it is more satiating per calorie than the other macronutrients, and it costs the body more energy to process. That makes a higher-protein diet easier to stick to at a deficit, which matters more in practice than the small metabolic difference.
The persistent claim that high protein damages healthy kidneys has not held up in the research. It does not follow that intake is irrelevant to kidney health — see the next section — but in a person with normal kidney function, a high-protein diet is not the risk it is often described as.
When protein needs a clinician
This calculator produces general guidance for healthy adults. Several situations sit outside that, and in them the number on this page is not the number to follow.
Chronic kidney disease is the main one. Reduced kidney function often calls for a restricted protein intake, individually set and monitored, and the ranges here would overshoot it substantially. Advanced liver disease can also change requirements in ways that need supervision. Pregnancy and breastfeeding both raise needs beyond what a standard adult calculation covers, and the increase is not uniform across a pregnancy.
The calculator is also built for adults from eighteen upwards. Children and adolescents have requirements that change with growth stage and are set differently. And anyone recovering from major surgery, burns or serious illness typically needs considerably more than any figure here, prescribed as part of their care.
Frequently asked questions
How much protein do I need a day?
It depends on your weight and how much you train. The WHO safe lower limit is 0.83 g per kg of body weight. The ADA range runs 0.8 to 1.0 g per kg if you are sedentary and 1.0 to 1.8 g per kg once you exercise regularly. For a 78 kg adult doing light exercise, that works out at a floor of 65 g and a training range of 78 to 140 g a day.
Why do the three recommendations differ so much?
Because they answer different questions. The WHO figure is a population floor below which deficiency risk rises. The ADA range is aimed at supporting training. The CDC band is a share of your total calories rather than a protein target in its own right, which is why it alone moves when you change the activity setting.
Is 0.8 g per kg enough?
It is enough to avoid deficiency, which is what it was set for, and for a sedentary adult it is adequate. It is not the same as optimal. If you lift, run, are eating at a deficit, are recovering from injury, or are over about sixty-five, there are good reasons to sit above it.
Can I absorb more than 30 g of protein in one meal?
You absorb essentially all of it — absorption is not the limit. What is limited is how much a single meal drives muscle protein synthesis, which plateaus somewhere around 25 to 40 g for most adults. The rest is used for energy rather than repair, so spreading intake across three or four meals gets more out of the same total.
Does high protein damage your kidneys?
Not in people with healthy kidneys, according to the available research. It is a different matter if kidney function is already reduced: chronic kidney disease often calls for restricted, individually supervised protein intake, and the ranges on this page would be well above it.
How much protein do I need to build muscle?
Most evidence points to returns tapering off around 1.6 g per kg of body weight, which is near the top of the ADA range. Going considerably higher is not harmful for a healthy adult but adds little, and those calories usually do more good as carbohydrate supporting the training itself.
Should I eat more protein when losing weight?
Generally yes. Protein is more filling per calorie than carbohydrate or fat and costs more energy to digest, which makes a deficit easier to hold. It also helps preserve muscle while you are losing weight, so more of what comes off is fat. The upper part of the ADA range is a reasonable place to sit while dieting.
These figures are general guidance for healthy adults aged 18 to 80, calculated from published recommendations, and are not personal dietary or medical advice. They do not apply to children or adolescents, in pregnancy or while breastfeeding, or to anyone with chronic kidney disease, liver disease, or recovering from major surgery, burns or serious illness — all of which change protein requirements, sometimes substantially and in both directions. If you have a medical condition, take medication that affects your nutrition, or are making a significant change to how you eat, please speak to a doctor or registered dietitian. Learn more about how we build our calculators and read our privacy policy.