GSM is a weight measure
GSM makes cloths with different sizes easier to compare. A heavier cloth may feel denser and hold more water, but the result also depends on the fibre, construction and finishing. A 300 GSM cloth with unsplit filament is not automatically better than a lighter split-fibre cloth for glass or grease.
Choose a range for the task
Use the intended surface, wiping or drying routine and selling format to shortlist weights. The catalogue includes lighter roll formats as well as household cloths and heavier car cloths. A proposed GSM range is a sourcing choice to verify with samples; it is not an automatic grade for lint, absorption, durability or reusability.
Measure the finished item
Weigh a clean, dry sample and measure its finished length and width. GSM is calculated from dry weight divided by area, with unit conversion applied consistently. Compare several samples rather than one piece, and record whether the edge is included in the finished measurement.
Put GSM into the order
The purchase order should state the target GSM, tolerance if required, finished size, blend and construction. The supplier should quote the same values on the sample label and carton documents. If the customer claim depends on GSM, use a test method agreed before production.
A specification you can send today
Send the item code or construction, material, size, colour, pack, target quantity and destination market. Ask the supplier to repeat these fields in the quotation and sample record. This keeps the commercial conversation tied to the product that will actually be produced. Related reading: How to Specify a Microfiber Cloth: GSM, Split Fibre and the Two Traps and A microfiber cloth supplier checklist for retail buyers.
Calculate GSM with consistent units
For a measured finished sample, divide dry mass in grams by the measured area in square metres. Write it as mass / (length × width), using length and width in metres. Define whether the measured specimen includes the edge and label, and use the same conditioning and measurement procedure for every sample.
For illustration, 27 g / (0.30 m × 0.30 m) = 300 g/m². These are arithmetic example values, not a measured SINOCLEAN result. A whole-cloth calculation that includes edging may differ from a fabric-specimen measurement, so agree the procedure before using it as an acceptance test.