Our absorbent fabric weights in gsm (grams per square meter), from heaviest to lightest:

340 gsm Hemp Fleece
300 gsm Bamboo Double Loop Terry, Organic Cotton Fleece
280 gsm Bamboo Fleece, Bamboo French Terry
260 gsm Bamboo Velour
250 gsm Microfiber Terry

This is a measure of how heavy a fabric is, NOT how thick it is - Bamboo French Terry is thinner than Bamboo Fleece for instance. This does give a rough absorbency comparison. All work well for cloth diapers.