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Size Wise

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Americans have not embraced the metric system, but many beads made in European and Asian countries are measured in millimeters. My own acceptance of metric measurements resulted from a love of and a need to better understand beads. Don't be put off by metric measurements! As a system, it is logical and beneficial to understand. Remember, if you can identify a 16th or 32nd of an inch, metric is a cakewalk in comparison.

From small to large, these important sizes are easy to get to know:

  • Size 11 seed beads measure approximately 2mm or slightly smaller.
  • Round Swarovski 2mm crystals are slightly larger than size 11 beads, but can make a sparkly (and somewhat expensive) substitute in some patterns.
  • Size 8 seed beads measure 2.5mm, close enough to work in place of 3mm beads, depending on the design.
  • Many manufacturers make 3mm beads; however, in sizes larger than 3mm, most beads are available only in even-numbered measurements.
  • Size 6 seed beads measure 3.5mm and can sometimes be a good substitute for a 4mm bead, depending on the pattern.
  • 4mm beads are probably the most popular size used in jewelry. In the case of Swarovski crystals, only 4mm bicones are offered in all available colors.

Many beads are small and mass-produced, so sizes can vary from one bead to the next. When I sampled and measured several brands and colors of size 11 beads, they varied from 1.7 to 2.2mm. For example, a Czech 3mm bead measured 2.6mm whereas a Swarovski crystal 3mm bead measured 2.9mm. To achieve these precise measurements, I used digital calipers.


Look on SomethingGlassy.com for size and conversion charts that make it easy to transition back and forth between inches and millimeters. Also, remember that the bead world loves to mix measurements. Strands of beads come in a standard 16-inch length, but the size of the beads on the strand is usually measured in millimeters.

A familiarity with sizes helps when shopping for beads or figuring a pattern from a photo. If visual estimations don't work well for you, bring a metric ruler when you shop. If you don't own a good ruler, go to Vendian.org to select and print out a free ruler. I recommend a ruler with centimeters and millimeters on one side and inches on the other.