Boston Terrier harness size chart: 16–24 in chest

How do I measure a Boston Terrier for a harness?

1. Stand the dog square. Use a soft tape around the deepest part of the ribcage, just behind the front legs.
2. Keep the tape level and snug, then leave room for two fingers under the chest strap.
3. Do not use neck circumference for the chest band. Neck and girth are different numbers.
4. Pick the smallest chart size whose maximum girth still covers your tape plus about one inch of ease.

What harness fit notes matter for a Boston Terrier?

A harness for a Boston Terrier is sized from chest girth, not from neck circumference. Typical adult chests sit around 16–24 inches at the deepest rib, behind the front legs. Leave about 1 inch of ease so two fingers fit under the strap.

At the low end of that range, expect the small band (16–22 in chest). At the high end, expect the medium band (22–28 in chest). One Boston Terrier does not size the next—the tape replaces the breed name.

The build to expect is a short, thick neck on a compact square body. A common miss on harnesses for this shape is related to how people already mishandle the neck: a long chest point that covers the eyes when they look up. For the chest strap, keep the tape level and on the ribs, not on the coat.

Keep the square modest. Their neck length does not match their chest width. If the strap sits on the soft belly or slides into the armpits, remeasure the deepest rib and move up or down one band—do not yank the neck strap tighter to compensate.

Chest girth and neck circumference are different measurements. Use the rib tape for harness bands; use the collar line for tied bandanas on the bandana calculator.