gsm vs. lb (paper weight)
Also known as: paper weight · stock weight
GSM (grams per square metre) and lb (pounds per 500-sheet ream) both measure paper weight, but they aren't directly comparable across paper types. A 100 lb gloss text is about 148 GSM; a 100 lb cover is about 270 GSM.
The same 'lb' rating means very different things depending on whether it's a text stock, cover stock, bond, or index. That's because lb is measured on different base sheet sizes per category. GSM is universal — every paper, regardless of type, can be compared by GSM. For business cards, 14pt (≈350 GSM) is standard; 16pt or 18pt feels heavier and more premium. For flyers and postcards, 100 lb gloss text (≈148 GSM) is the workhorse weight.