Using a flexible measuring tape (or leash), measure from just behind the front legs all the way around your dog. You are measuring the circumference of the body just behind the front legs, like measuring for a "belt." Then go to the Products page (SENSE-ible® or SENSE-ation®) and select the proper size using the girth measurement.
Please note that the measurement is the best way to get the correct size - DO NOT USE THE WEIGHT RANGE to select size.
A = Measuring tape position (just behind front legs)
B = Start and finish at this point