Paper weight conversion
Pounds (lb) to GSM Conversion
Convert U.S. basis weight to grams per square meter. Pick the paper category, enter the lb value and read the GSM equivalent.
lb to GSM calculator
Standard U.S. paper weights in GSM
Bond/Writing (17 × 22 in basis)
| Basis weight | GSM |
|---|---|
| 16 lb | 60.2 |
| 20 lb | 75.2 |
| 24 lb | 90.2 |
| 28 lb | 105.3 |
| 32 lb | 120.3 |
| 36 lb | 135.4 |
| 40 lb | 150.4 |
20 lb and 24 lb Bond are the most common office papers.
Text/Book/Offset (25 × 38 in basis)
| Basis weight | GSM |
|---|---|
| 50 lb | 74.0 |
| 60 lb | 88.8 |
| 70 lb | 103.6 |
| 80 lb | 118.4 |
| 100 lb | 148.0 |
| 120 lb | 177.6 |
Text weights cover book pages, flyers and brochure interiors.
Cover (20 × 26 in basis)
| Basis weight | GSM |
|---|---|
| 65 lb | 175.8 |
| 80 lb | 216.3 |
| 100 lb | 270.4 |
| 110 lb | 297.5 |
| 130 lb | 351.5 |
Cover weights are card stocks for covers, cards and packaging.
Formula
Example for 65 lb Cover: the basis sheet is 20 × 26 in = 0.3355 m². So 65 × 453.592 ÷ (0.3355 × 500) ≈ 175.8 GSM.
Frequently asked questions
What is 20 lb paper in GSM?
20 lb Bond — standard U.S. copy paper — is about 75.2 GSM, very close to the 80 GSM office paper used in metric markets.
What is 100 lb Cover in GSM?
100 lb Cover is about 270.4 GSM — a sturdy card stock used for covers and postcards.
Why does 100 lb Text weigh less than 100 lb Cover?
Because Text uses a much larger basis sheet (25 × 38 in) than Cover (20 × 26 in). 500 large thin sheets can weigh the same as 500 small thick sheets, so the same lb number describes different papers.
What is the exact lb to GSM formula?
GSM = lb × 453.59237 ÷ (basis area in square meters × 500). The basis area depends on the paper category.