Protein Calculator

How this protein calculator works

The math is simple: your body weight in pounds times a factor that depends on what you are trying to do and how old you are. That is how the Dietary Reference Intakes and the sports-nutrition literature both frame it.

The floor is the RDA, 0.36 g per pound (0.8 g per kg). That number was set to prevent deficiency in a sedentary adult, not to help you keep muscle while dieting or lifting. Active adults land at 0.55–0.7 g per pound. If you are trying to build muscle, or lose fat without losing muscle, the range moves up to 0.7–1.0 g per pound. Adults 65 and older get their own row: 0.45–0.55 g per pound (1.0–1.2 g per kg), the range the PROT-AGE study group recommends for healthy older people.

One line of math, using a 160 lb adult who lifts twice a week: 160 × 0.7 = 112 g a day. The calculator also splits that total across your meals, because 25–40 g per sitting is what the muscle-building response seems to want. And if your BMI is over 30, it uses a goal weight instead of your current weight, so the target does not balloon with body fat that does not need feeding.

How to read your result: grams of protein per pound and per kg

Find your row. Most people belong in the second or third one, and "protein for weight loss" is the third row, not the first — you want more protein when calories go down, not less. Women use the same factors as men; the totals come out lower only because body weight is usually lower.

The 0.7 g per pound number is not arbitrary. In the 2018 meta-analysis by Morton and colleagues, 49 resistance-training trials pooled together showed gains in lean mass leveling off at about 1.6 g per kg per day. Above roughly 1 g per pound, no controlled study has shown extra muscle from extra protein in healthy adults.

What 30 g of protein looks like

Once you have a daily number, the practical question is what 30 g is on a plate. Each portion below lands at about 30 g.

Where the number misleads

Kidney disease. If you have chronic kidney disease, this calculator is not for you. People with CKD who are not on dialysis are usually asked to eat less protein, not more, and the target belongs to your nephrologist or renal dietitian. In healthy kidneys, intakes up to about 1 g per pound have not shown harm in trials, but nobody has studied decades of it.

Very high intakes. Beyond 1 g per pound the benefit curve is flat. More protein at that point mostly means fewer calories left for fiber, fruit and fat, and a grocery bill that grows faster than your muscle.

Plant protein. Grams are not all equal. Most plant proteins carry less leucine, the amino acid that switches muscle building on, and are digested less completely. If you eat mostly plants, aim for the top of your range, lean on soy and pea, and mix sources across the day.

Body fat. The factor multiplies body weight, and fat tissue needs very little protein. That is why the tool switches to goal weight above a BMI of 30.

Powder is food, not a supplement. Whey and pea protein are dried milk and dried peas. They do nothing a chicken breast cannot; they are simply faster and, per gram, often cheaper.

What to do with it

1. Anchor breakfast first. The meal most Americans skimp on is the morning one. Our piece on protein at breakfast and belly fat shows what 30 g looks like before 10 a.m., and why it changes what you eat at 4 p.m.
2. Divide, don't pile. Split your daily number across three or four meals of 25–40 g each. A 90 g day is three meals of 30; a 140 g day is four meals of 35. One giant dinner does not count the same.
3. Lift something. Protein above the RDA only builds muscle when muscle is asked to work. Two sessions a week of resistance training is enough to start. After 40, creatine is the one supplement with real trial data next to protein.
4. Weigh food for one week. Most people guess their protein intake 20–30 g too high. Seven days with a food scale and a free tracking app calibrates your eye.
5. Over 65, treat the higher row as the floor. Muscle loss speeds up after 65 and older muscle responds less to each meal, which is why PROT-AGE wants 25–30 g per meal. Our guide to supplements worth taking after 50 covers what pairs with it.