Anyone who's ever stared slack-jawed at a rack of shoelaces knows it's not easy to figure out the correct length for a new pair of shoes. There's no need to guess, however. Instead, a few rules of thumb can lead you to the perfect pair of laces for that shoes or boots that need them.

Check the package for clues. For instance, you may see a description such as, “Brown and Yellow 6-8 Eyelet.” These usually offer a basic estimate of the lace to shoe ratio, which will vary depending on the shoe and your method of lacing.

Use a length calculating system, such as that developed by Ian W. Fieggen, who has produced an extensive website devoted to the ins and outs of shoelaces. Fieggen, one of the world's experts on shoelaces, has developed a convenient calculator which can be used on its own or in combination with the underlying algorithms. His formula crunches shoelace lengths for some 50 lacing styles from several data points, including pairs of eyelets, horizontal distance, vertical distance, width of lugs, and length of ends. For metric to English conversion, find a link in References.

Note the difference between active and dress shoes. Dress shoes have fewer eyelets and require shorter laces. The basic rule: for active shoes, multiply the number of eyelets by seven to get the length in inches. For dress shoes, the length will be relatively consistent, ranging between between 18 and 27 inches.