Trek Harness Size Chart

Choose your dog’s harness size primarily by measuring the widest part of the chest, directly behind the front legs. Weight can be used as a secondary reference.

Size Recommended Weight Chest Girth
Small 15–30 lb 17–24 in
Medium 25–55 lb 22–31 in
Large 40–75 lb 26–35 in
Extra Large 75–105 lb 31–41 in

How to Measure

Wrap a soft measuring tape around the widest part of your dog’s ribcage, directly behind the front legs.

Keep the tape flat and secure without pulling it tightly. If your dog falls between sizes, choose the larger size for a more comfortable and adjustable fit.