Protein Intake Calculator

How much protein you actually need

The number most people remember — 0.8 grams per kilogram of body weight — is the Recommended Dietary Allowance. It answers a deliberately narrow question: what is the smallest intake that keeps a sedentary adult out of deficiency? It was never meant to describe the intake that builds muscle, preserves lean mass during a diet, or keeps a 70-year-old strong enough to carry shopping up the stairs. Position stands from the International Society of Sports Nutrition and the American College of Sports Medicine put the useful range for people who train at roughly 1.4 to 2.0 g/kg, and higher still for lifters eating in a calorie deficit.

This calculator takes your body weight, converts pounds to kilograms where needed, and multiplies it by the band that matches what you are doing with your body. It returns a range rather than a single figure because the research supports a range: below the low end you leave results on the table, above the high end you spend money and appetite for no measured return.

Worked example 1: a 75 kg lifter building muscle

Select "building muscle" at 75 kg and the band is 1.6 to 2.2 g/kg: 120 g at the bottom, 165 g at the top. Split over four meals that is 30 to 41 g each, which comfortably clears the roughly 0.4 g/kg per-meal dose that maximises muscle protein synthesis in most studies. Translated into food, 150 g of protein is about five 100 g servings of cooked chicken breast — or, more realistically, 200 g of chicken (62 g), a 250 g tub of Greek yoghurt (25 g), a whey shake (25 g), 150 g of lentils (13 g) and roughly 25 g scattered through bread, oats, rice and vegetables across the day.

Worked example 2: 90 kg and cutting

The same person dieting picks "losing fat, keeping muscle" and gets 1.8 to 2.4 g/kg — 162 to 216 g per day at 90 kg. That looks aggressive next to the bulking figure, and it is deliberate. When calories are low, the body is more willing to break down muscle for amino acids, so the protective effect of high protein matters more, not less. Protein is also the most satiating macronutrient per calorie, which is a practical advantage when you are hungry. The trade-off is that at 216 g of protein plus training fuel, there is not much room left for fat and carbohydrate, so most people sit near the lower end and accept it.

Worked example 3: a 68 kg 70-year-old

Choosing "over 65" gives 1.0 to 1.2 g/kg, or 68 to 82 g per day — modest in total, but the distribution matters more here than at any other age. Older muscle shows anabolic resistance: the same 20 g dose that switches on synthesis in a 25-year-old often does not in a 70-year-old, and the threshold sits closer to 30 to 40 g of high-quality protein containing about 2.5 to 3 g of leucine. Three solid meals beat five snack-sized ones. Pair that with two resistance sessions a week and you have the best-evidenced intervention against sarcopenia that exists.

Choosing your band honestly

Most people overestimate their activity level and underestimate their intake. "Active lifestyle" means genuine structured training several times a week, not a step count. If you lift three or more times a week with progression, use the muscle band. If you run or cycle long distances, the endurance band accounts for the small amount of protein oxidised as fuel during long sessions plus the repair demand afterwards. If you are simply eating better without training, the sedentary-to-active range is where you belong, and the low end is fine.

One important adjustment: if you carry a lot of body fat, scaling protein to total body weight inflates the target, because fat tissue has little protein demand. Use your goal weight or an estimate of lean body mass instead — a 130 kg person aiming for 90 kg should calculate on something close to 90, not 130. At the other end, very lean athletes in a hard deficit are the group with genuine evidence for intakes at or above 2.4 g/kg.

Planning it in real food

Numbers are easy, groceries are the hard part. Useful anchors: 100 g of cooked chicken breast is about 31 g of protein, a large egg 6 g, 100 g of canned tuna 25 g, 200 g of Greek yoghurt 20 g, a scoop of whey 24 g, 100 g of firm tofu 16 g, 100 g of cooked lentils 9 g. Hitting 150 g per day usually means one substantial protein source at every meal plus one deliberate top-up — a shake, a yoghurt, a tin of fish. If your total keeps landing short, it is almost always breakfast: cereal, toast and fruit is a 10 g start to a 150 g day.

Where this calculator stops

It assumes a healthy adult. Chronic kidney disease changes the answer completely, and protein there is managed by a clinician, not a web page. Pregnancy and lactation raise requirements by roughly 25 g per day in ways this band model does not capture. Children and adolescents scale differently again. The ranges also blur at the edges — an untrained beginner grows on far less than 1.6 g/kg because their limiting factor is training stimulus rather than substrate, while a drug-free advanced lifter is unlikely to find anything above 2.2 g/kg doing much. Treat the output as a target to aim at over a week, not a daily quota to hit exactly.