What the number tells you
A higher GSM means more cotton in every square metre: the towel feels thicker and absorbs more, but it is heavier to launder and slower to dry. A lower GSM is lighter, dries faster and costs less to wash.
Matching weight to use
As a general guide, light towels suit gyms, pools and high-turnover sites where drying time matters; mid-weight towels suit most guest rooms; the heaviest towels are kept for premium rooms and spas.
Look beyond GSM
Yarn type, pile height, the border and the hem decide how long a towel lasts in commercial laundering. Ask for a sample and wash it several times before ordering in volume.