How much protein do you actually need?
The official dietary reference intake for protein — 0.8g per kilogram of bodyweight — is set to prevent deficiency in a sedentary adult, not to optimize muscle, recovery, or body composition. For anyone training regularly, the useful range sits considerably higher, which is why this calculator scales the target with activity level rather than using a single fixed number.
Sports nutrition research generally supports 1.6-2.2g/kg for people doing regular resistance training, with intake above roughly 2.2g/kg showing little additional benefit for muscle protein synthesis in most studies — the body has a practical ceiling for how much dietary protein it can use for muscle building at any given time.
Distributing protein across the day
Total daily protein matters most, but timing isn't irrelevant. Spreading intake across three to four meals, each contributing roughly 20-40g, tends to maximize muscle protein synthesis more effectively than consuming the same total in one or two large meals, because the body can only use so much protein for muscle building in any single feeding window.
During a calorie deficit
Protein needs typically rise, not fall, during a weight-loss phase — higher protein intake helps preserve lean mass while in a calorie deficit, which is part of why the "active" and "athlete" presets above sit toward the higher end of the typical research range.