THE NUMORIX GUIDE
How to use the Protein Intake Calculator
Last reviewed September 14, 2026
What this calculator does
The engine first converts pounds to kilograms with weight x 0.
Formula and method
The engine first converts pounds to kilograms with weight x 0.453592 when needed. It selects a base factor of 0.8, 1.0, 1.2, 1.6, or 2.0 g/kg for sedentary, light, moderate, intense, or athlete activity. It adds 0.2 g/kg for a lose goal or 0.3 g/kg for gain, then reports body weight x adjusted factor and a range from 90% to 110% of that result.
Variables and inputs
Enter weight in kg or lb, select one of five activity levels, and select maintain, lose, or gain. The outputs are grams of protein per day: a central target and a range. The goal adjustment is an engine rule, not a clinical protein prescription.
Worked example
For 70 kg, moderate activity, and a maintain goal, the factor is 1.2 g/kg, so 70 x 1.2 = 84.0 g/day; the displayed range is 75.6 to 92.4 g/day. If the same person selects gain, the factor becomes 1.5 and the target becomes 105.0 g/day with a 94.5 to 115.5 g range.
How to interpret the result
The result is a planning target scaled to body weight and the selected profile. It is not a statement that one exact intake is necessary, and the range should be considered alongside total calories, training load, food pattern, age, and medical status.
Common mistakes to avoid
Match the weight number to the selected unit; entering 154 as kilograms instead of pounds changes the target dramatically. Do not treat the lose or gain selector as a required protein increase for every person, and do not convert grams of protein directly into total daily calories without accounting for the rest of the diet.
Assumptions and limitations
The activity factors and goal additions are simplified assumptions and do not adjust for lean mass, pregnancy, older age, injury, endurance volume, or kidney and liver disease. The engine does not evaluate protein quality, meal distribution, total energy, or a clinician's prescribed diet. People with medical conditions should get an individualized target.