Paper Weight Converter
Convert between gsm and pounds for any paper grade, and see the same sheet expressed as a basis weight in every grade — so a supplier’s label never trips you up again.
Converted weight
Same paper, other grades
| Grade | Equivalent basis weight |
|---|---|
| Bond / Writing / Ledger | 57.5 lb |
| Text / Book / Offset | 146.1 lb |
| Cover / Cardstock | 80 lb |
| Index | 119.6 lb |
| Tag | 132.9 lb |
| Bristol | 98.6 lb |
| Newsprint | 132.9 lb |
How paper weight works
Grammage (gsm) is the honest, absolute measure: the weight of a one-metre square of the paper. The US “pound” system instead weighs a ream of 500 sheets at that paper’s basis size, and every grade uses a different basis size. That is why an 80 lb cover and an 80 lb text feel nothing alike — they were weighed on different-sized sheets.
This converter uses the standard formula, gsm = lb × 1406.14 ÷ (width × height in inches), so you can move between the two systems for whichever grade you are holding, and read the cross-grade equivalents at a glance.
Frequently Asked Questions
Why does the same gsm give a different pound number for each paper?
US basis weight is the weight of a 500-sheet ream cut to that grade's basis size — and each grade uses a different basis size. Bond is weighed at 17×22 inches, text at 25×38, and cover at 20×26. So 216 gsm is 80 lb cover but about 146 lb text, even though it is the same physical sheet. gsm is the only absolute measure; pounds only make sense once you name the grade.
What is gsm?
Grams per square metre — the mass of one square metre of the paper, regardless of how it is cut. Copy paper is around 80 gsm, a greeting-card base is 216–300 gsm, and heavy cardstock runs 300 gsm and up. Because it is tied to a fixed area, gsm compares directly across every paper type.
Which grade should I pick?
Match the grade to the paper you actually have. Choose Bond for copy and inkjet paper, Text/Book for patterned craft paper and book blocks, and Cover/Cardstock for card bases and invitations. The tool also lists the equivalent basis weight in every grade so you can cross-check a supplier's label.
How exact is the conversion?
The formula is exact for the standard basis sizes; the small differences you see against a manufacturer's stated figure come from their rounding. Treat the result as accurate to within a pound or a couple of gsm.
Reference tool only. Basis-size conventions and manufacturer rounding vary; check a swatch or spec sheet when an exact weight matters for printing or postage.