Convert
Basis Weight to GSM:
| Grade |
Base
Size |
Sq
Inches (Area) |
| Office
and Writing Papers |
17
x 22" |
374 |
| Offset
and Book |
25
x 38" |
950 |
| Vellum
Briston |
22.5
x 28.5" |
641.25 |
| Index |
25.5
x 30.5" |
777.75 |
| C1S
Bristols |
24
x 36 " |
864 |
| Cover |
20
x 26" |
520 |
Formula:
Multiply
basis weight by 1406.13 and divide by the square inches of the base
sheet.
Example
: C1S Board of basis weight 167 lbs
GSM
= ( 167 x 1406.13 ) /
864 =
272 gsm
To
convert from GSM to lbs, the reverse is done:
Multiply
the GSM by the square inches of the base sheet and divide by 1406.13
