The quantity of fabric on a bolt can vary depending on the type of fabric. Typically, a standard bolt of fabric contains around 15 to 20 yards of fabric. However, it's important to note that this may change depending on the fabric's width and thickness. For instance, a bolt of canvas or denim may contain fewer yards due to their heavier weight, while a bolt of thinner, lighter material like silk or chiffon may contain more yards. Therefore, it's always a good idea to check with the fabric supplier for the exact yardage on a specific bolt of fabric.