100 lb cover paper
270 g/m²
100 lb cover · basis size 20 × 26 in · Business cards, book covers, postcards and folders.
Where 270 gsm comes from
An American basis weight is the weight of 500 sheets at that grade's basis size. For cover that size is 20 × 26 inches, so:
500 sheets × 20 × 26 in = 260,000 in² = 167.7 m²
100 lb = 45,359 g
45,359 g ÷ 167.7 m² = 270 g/m²The same number, a different paper
100 lb is not one weight. Because every grade is weighed at its own sheet size, the same pound figure describes papers that are nothing alike:
| Grade | Basis size | 100 lb is | vs cover |
|---|---|---|---|
| Cover | 20 × 26 in | 270 gsm | — |
| Bond / Writing | 17 × 22 in | 376 gsm | 1.39× |
| Text / Book | 25 × 38 in | 148 gsm | 0.55× |
| Index | 25.5 × 30.5 in | 181 gsm | 0.67× |
| Tag | 24 × 36 in | 163 gsm | 0.60× |
| Bristol | 22.5 × 28.5 in | 219 gsm | 0.81× |
This is the reason to ask for gsm. One number, no grade, no ambiguity — 270 gsm is 270 gsm whoever is printing it.
Frequently asked questions
What is 100 lb cover paper in gsm?
270 gsm. 100 lb means 500 sheets at the cover basis size of 20 × 26 inches weigh 100 pounds.
Is 100 lb cover the same as 100 lb text?
No, and the difference is large. 100 lb cover is 270 gsm; 100 lb text is 148 gsm — 1.83 times as heavy. The pound number is the weight of 500 sheets at a size that differs by grade, so it cannot be compared across them.
What is 100 lb cover used for?
Business cards, book covers, postcards and folders. At 270 gsm: board rather than paper, needing a press with a straight paper path.