Guides
GSM and SAP explained: how to read an underpad or diaper spec sheet
10 August 2026
Every continence product spec sheet leads with two numbers: GSM and SAP loading. Neither means much on its own, and neither is printed on the packaging most facilities actually see, which is why so many standing orders get compared on price per carton instead of on what the product actually does. Both numbers are simple once you know what they measure.
GSM: the weight of the material, not the pad
GSM stands for grams per square metre. It is a fabric industry measurement, not a whole-product one, and on a continence pad it usually describes the non-woven top sheet or the backing film rather than the finished pad's total weight. A higher GSM top sheet is thicker and more resistant to tearing under load; a higher GSM backing film is less prone to pinholing over a long wear period.
It is worth asking for the GSM on a specific layer, not the product as a whole, when comparing two suppliers. "Similar GSM" on a spec sheet from two different factories can describe fabrics with noticeably different feel and strength if the layer being measured is not the same one.
SAP loading: how much fluid the core actually holds
SAP is superabsorbent polymer, the material inside the absorbent core that turns liquid into a gel and locks it away from the surface. SAP loading is usually expressed in grams of SAP per pad, and it is the number that correlates most directly with how long a product can go between changes before it leaks or feels wet against the skin.
A pad with a higher SAP loading is not automatically the right choice. Over-specifying absorbency adds cost per unit for capacity a resident's actual output does not need, and under-specifying it shows up fast as leakage or more frequent changes than the roster is built around. The loading has to match the wear time and the output level, which is a clinical decision as much as a purchasing one.
Comparing against what you buy today
The fastest way to compare a quote against your current supplier is to ask both for GSM by layer and SAP loading per pad on the exact size and format you use, then hold the two spec sheets side by side. If a supplier will not provide both numbers, that is worth noting on its own.
We publish full specification tables, including GSM and SAP loading, on every product in our continence care range, and will match a competitor's specification gram for gram where the construction allows it. Samples go out before any volume is committed, since absorbency and feel are not things to judge from a spec sheet alone.
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