A clothing size chart for boys shows clothing size according to a boy's hips, chest and waist measurements not to mention his height and weight. Height, hips, chest and waist measurements are mentioned in inches while weight is mentioned in pounds.
Examples of a clothing size chart for boys can be seen on Nike and Cute Well-Dressed Kids. Different clothing manufacturers have different clothing size charts. For example, Nike mentions pants sizes for boys as XS, M, S, L and XL while Cute Well-Dressed Kids mentions clothing sizes for boys as 2T, 3T, 4T, 4 Reg, 8, 10, 14, 12 and others. For any measurement that is borderline, Nike advises to pick a bigger size for loose-fitting pants and a smaller size for tight-fitting pants.