Protein Calculator

The multipliers behind each goal

Pounds are converted to kilograms at 0.453592 kg per lb before the multiplier is applied, and both ends of the range are rounded to whole grams. So 165 lb becomes 74.8 kg, and with Build muscle selected the result is 120–165 g, the same as entering 75 kg directly.

The lowest figure, 0.8 g per kg, is the Recommended Dietary Allowance for sedentary adults, the amount that prevents deficiency rather than an optimum. The 1.6–2.2 g per kg band is the range most resistance-training research points to for maximising muscle gain, with little extra benefit above it.

Why you get a range, not one number

Protein needs are not precise enough to justify a single figure. The bottom of your range is enough for most people in that category; move towards the top if you are in a calorie deficit, over 60, mostly plant-based, or training hard several times a week. If you are not sure, aim for the middle and adjust after a few weeks based on recovery and hunger.

Turning the grams into food

A 120 g target spreads comfortably over three or four meals of 30–40 g each: eggs and yogurt at breakfast, a chicken or lentil lunch, and fish or tofu at dinner. Spreading it out matters more for muscle building than hitting the total in one sitting.

Limits of a weight-only estimate

• The formula multiplies total body weight, so a person carrying a lot of body fat gets a high figure. Entering a realistic goal weight instead gives a more sensible target.
• There is no adjustment for age, pregnancy or breastfeeding, all of which raise requirements.
• People with kidney disease are usually told to limit protein and should follow their clinician's figure rather than any of these multipliers.
• The result is grams of protein, not grams of meat or beans: 100 g of chicken contains about 31 g of protein.
• Switching the toggle between kg and lb keeps whatever number is in the weight field, so re-enter your weight after changing units.

Choosing between the three goals

Pick General health if you exercise little or lightly and simply want to eat enough. Pick Active / fitness if you run, cycle, play sport or do gym classes a few times a week. Pick Build muscle if you lift weights with the aim of adding size or strength, or if you are dieting and want to keep the muscle you have, since higher protein helps preserve lean mass in a deficit.