How to Measure a Brush


Brush sizing can vary by brand, making it difficult to determine which size best suits your painting goals. Our chart solves this problem by providing a standard which is easy to understand. Since the vast majority of brushes are handmade, it is important to note that there will always be some discrepancy in brushes of the same size.

Brushes may be measured by length, diameter, and width.

  • Measuring the Length

    Length: The distance from the edge of the ferrule out to the tip of the hair in the center of the brush.

    In this example, the length of the brush is measured from the bottom of the chart. Therefore, the brush at left measures 28.575 mm long.

  • Measuring the Diameter and Width

    Diameter: The distance of the hair at the opening of the ferrule.

    Width: The distance across the hair above the opening of the ferrule. Width does not refer to the width of a stroke a brush will make, which varies depending on the amount of pressure applied, the media used, the brush angle, and the brush hair or fiber.

    In this example, the diameter or width is measured by laying the brush across the right edge of the chart. Therefore, the brush in the lower corner measures 17.463 mm wide.

If you would like to measure a brush you already own, download and print the PDF.

To learn more about brushes, visit Brush Shape Differences and Brush Fiber Differences.