Paper & Card Weight Guide
Paper weight can be confusing — especially when you encounter both GSM (used in the UK and Europe) and the US pound-based system. This guide explains what GSM means, covers all common paper and card weights, tells you what each is best used for, and helps you convert between UK and US systems.
What Is GSM?
GSM stands for grams per square metre. It measures the weight of a single sheet of paper or card if it were exactly one square metre in size. A higher GSM means a thicker, heavier sheet. In the UK, GSM is the standard measurement for all paper and card products.
The boundary between “paper” and “card” is generally around 170–200 gsm. Below that, it's considered paper; above that, it's card or cardstock.
Common Paper & Card Weights
| GSM | Type | Approx. Thickness | Common Uses |
|---|---|---|---|
| 35–55 | Tissue / newsprint | 0.05–0.08 mm | Newspapers, tissue paper, pattern tracing paper |
| 75–80 | Standard paper | 0.10–0.11 mm | Everyday printing, photocopier paper, letter writing |
| 90–100 | Quality paper | 0.11–0.13 mm | Quality stationery, letterheads, inkjet photo paper (matte) |
| 120 | Heavyweight paper | 0.15–0.17 mm | Leaflets, flyers, premium stationery, book covers (paperback) |
| 130–150 | Thick paper | 0.17–0.20 mm | Poster paper, magazine covers, art prints |
| 170–200 | Light card | 0.22–0.27 mm | Craft card, light cardstock, programme covers, certificates |
| 210–240 | Medium card | 0.27–0.32 mm | Greetings cards (single fold), photo prints, report covers |
| 250–280 | Heavy card | 0.32–0.38 mm | Business cards, postcards, wedding invitations, book covers |
| 300–350 | Very heavy card | 0.38–0.48 mm | Luxury business cards, packaging, box making, mount board |
| 400+ | Board | 0.50+ mm | Box board, rigid packaging, book binding board |
UK GSM vs US Paper Weight
The US system measures weight in pounds (lb) based on a ream (500 sheets) of paper at its uncut “basis size”, which varies by paper type. This makes direct comparison confusing. Here are the most common equivalents:
| GSM (UK/EU) | US Bond (lb) | US Cover (lb) | Typical Use |
|---|---|---|---|
| 75 | 20 lb | — | Standard copy paper |
| 90 | 24 lb | — | Quality letterhead |
| 120 | 32 lb | — | Heavyweight stationery |
| 163 | — | 60 lb | Light card |
| 216 | — | 80 lb | Standard cardstock |
| 270 | — | 100 lb | Heavy cardstock |
| 350 | — | 130 lb | Very heavy card / board |
Convert Paper Weights
Use our paper weight converter for instant conversions between GSM, US bond, and US cover weight:
- Paper Weight Converter — convert between GSM, US bond, US cover, and other paper weight systems
Thickness values are approximate and vary with paper composition (coated vs uncoated, cotton vs wood pulp). The same GSM paper can feel different depending on its finish and fibre content. Always request a sample swatch before ordering large quantities for craft projects.