Proteins are the major building blocks of the body, serving most notably as the fundamental architects ofmuscle and fueling its growth and repair. But they also direct countless other biological functions. Eachprotein has its own structure and role, and with an estimated 20,000encoded by thehuman genome—many with multiple variants, or proteoforms—they form a remarkably versatile group that contributes to nearly every aspect of biological activity, fromcell function to immune protection.

Encyclopædia Britannica’s protein calculator provides a general estimate of daily protein needs based on personal metrics and fitness level. By applying established dietary guidelines and precise formulas, it calculates daily protein requirements according tobasic recommendations, activity level, athletic requirements, or medical considerations. Understanding these needs can help individuals optimize their diet to support various goals, including muscle growth and weight management.