To determine approximate GSM (grams per square meters) of a given
fabric, you can use following formula. One of my colleagues used to use
this formula in testing lab. In case different counts of warp thread or
weft thread is used then this formula will not give you correct GSM. It
is also known as conversion formula from fabric construction to fabric
weight.
Fabric GSM = (EPI/warp count + PPI/Weft count) x (100+crimp %) X 0.2327
For example, construction of a fabric is 40 X40 /120 X 60 and warp and weft crimp is 6%. Then GSM of this fabric will be,
GSM = (120/40 + 60/40) X (100+6%) X 0.2327
GSM =104.77
I found others to use this formula with different multiplying factors.
Fabric GSM= ((EPI/warp count X 1.1) + (PPI/weft count x 1.04)) x 23.5 By Dharmi
Where 1.1 and 1.04 are warp and weft crimp factors respectively.
