Paper Weight Converter: GSM to lb
Convert paper weight between GSM, lb text, lb cover, and lb bond.
Find the right paper weight for printing, crafting, cardstock, and packaging projects.
Paper Weight Explained
Paper weight is measured differently in the US than in the rest of the world. The US system is based on the weight of 500 sheets cut to a standard parent sheet size. The metric system uses GSM, grams per square meter, which is universal and needs no footnotes.
Conversion factors:
| From | To GSM | Parent sheet |
|---|---|---|
| lb text (offset) | x 1.48 | 25 x 38 in |
| lb cover | x 2.704 | 20 x 26 in |
| lb bond (writing) | x 3.76 | 17 x 22 in |
Each factor is just arithmetic on the parent sheet, not a lookup. Cover stock is 20 x 26 inches, so 500 sheets cover 500 × 20 × 26 = 260,000 square inches, which is 167.74 square meters. A pound is 453.59 grams, so one pound of basis weight spreads to 453.59 ÷ 167.74 = 2.704 GSM. The other two rows come out the same way.
Examples:
- 20 lb bond (copy paper) = 75 gsm
- 24 lb bond (premium copy) = 90 gsm
- 65 lb cover (thin cardstock) = 176 gsm
- 80 lb cover (standard cardstock) = 216 gsm
- 100 lb cover (heavy cardstock) = 270 gsm
Common paper types by GSM:
| GSM | Type | US Equivalent |
|---|---|---|
| 30-45 | Tissue, tracing paper | not sold by lb |
| 45-55 | Newsprint | not sold by lb |
| 60-70 | Lightweight book | 40-45 lb text |
| 75-90 | Copy/printer paper | 20-24 lb bond |
| 90-120 | Premium printer | 60-80 lb text |
| 130-160 | Flyer, brochure | 90-100 lb text |
| 160-200 | Light cardstock | 60-75 lb cover |
| 200-250 | Standard cardstock | 80-90 lb cover |
| 270-350 | Heavy cardstock | 100-130 lb cover |
| 350-400 | Board, poster | not sold by lb |
Why two US systems (text vs cover)? Text weight uses a larger parent sheet than cover weight. The same paper measured on different parent sheets gives different lb numbers. This is why 80 lb text does NOT equal 80 lb cover. Cover is nearly twice the weight: 118 gsm against 216.
Buying tip: Always check GSM when ordering paper from international suppliers. US lb weights without specifying text vs cover vs bond are ambiguous.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.