The whole range of bathroom vanity variants by virtue of measurements has several bases, including the heights, widths, and depths. Meanwhile, talking about such 24 vanity (read: 24-inch bathroom vanity), that is based on how wide the cabinets are (the widths). In general, based on the width sizes, the variants of bathroom vanity have sizes is between 18 inches and 60 inches.
Going to the market and looking for some bathroom vanity, sometime you may find choices like 24 bathroom vanity, 36 bathroom vanity and 42 bathroom vanity. Those are all based on size, exactly the size of the width of some vanity. The part of the vanity that is used as the basis of such naming style is the measurement of the cabinets.