North America and Europe use different systems for estimating paper weight. The North American system goes back to medieval Europe and uses the weight in pounds of a ream (500 sheets) of a particular size of paper to give a basis weight. Typical weights for book printing paper are:
- Book - 30 to 100 pounds
- Text - 70 -80 pounds
- Cover - 60-100 pounds
The European system is based on grams per square meter (gsm). A typical photocopier or laser printing paper will be 80gsm. Paper for printing most books will be upwards of 110 gsm, while cover stock will be heavier at 140 gsm plus. Cover stock in both regions is usually available in coated and uncoated varieties.