PSMF protein calculator: how much protein do you need?
Enter your sex and height. The calculator estimates your ideal body weight and multiplies it by 1.2 and 1.5 g of protein per kg, the range used in the Cleveland Clinic PSMF protocol. Your current weight is not needed, and that is on purpose.
Why ideal body weight and not current weight
A PSMF gives you enough protein to protect muscle and organs. Body fat doesn’t need protein. If you used your current weight, a person carrying a lot of fat would get a target far higher than their muscle needs, and those extra calories would cut into the deficit.
The Cleveland Clinic review sets protein at 1.2 to 1.5 g per kg of ideal body weight, and the clinic’s own protocol uses 1.5 g/kg. The calculator shows the full range so you and your doctor can choose.
The formula
The calculator uses the Devine formula for ideal body weight. Pharmacists use it to dose some drugs. A 2000 review in the Annals of Pharmacotherapy traced where these equations came from and found that the common versions give similar answers.
- Men: 50 kg + 2.3 kg for each inch over 5 feet
- Women: 45.5 kg + 2.3 kg for each inch over 5 feet
The formula was not built for people under 5 feet, so the calculator stops there and asks you to get a number from your doctor.
Worked example
A woman who is 5 feet 6 inches tall:
- Ideal body weight: 45.5 + (2.3 × 6) = 59.3 kg
- Low end: 59.3 × 1.2 = 71 g of protein per day
- High end: 59.3 × 1.5 = 89 g of protein per day
Her target is 71 to 89 g a day whether she weighs 80 kg or 130 kg.
Ideal body weight or lean body mass?
Some people set PSMF protein from lean body mass instead. That approach is common in bodybuilding circles, where people are already lean and use a short PSMF to cut fat. For people with obesity, the clinical protocol uses ideal body weight. If you want to see your lean body mass anyway, use the lean body mass calculator. The two numbers are often close for someone of average build, and further apart for very muscular people.
Common mistakes
Counting the weight of meat instead of grams of protein. 100 g of raw chicken breast is not 100 g of protein; it is roughly 22 to 24 g, depending on the cut. Check the label or a nutrition database.
Picking fatty protein. The protocol limits protein foods to under 3 g of fat per ounce. Lean poultry, white fish, shellfish, egg whites, fat-free Greek yogurt and low-fat cottage cheese fit. Ribeye and regular ground beef don’t.
Going far over the target “to be safe”. Extra protein adds calories, and the review notes that high protein intake can raise uric acid.
Skipping supplements. Protein alone does not cover your needs on 800 calories or less. The protocol adds a multivitamin plus potassium, calcium, magnesium and sodium. Get the doses from your doctor.
Read what PSMF is and who should avoid it before you use this number.