Weight charts assume an average shape. Dogs are not average. Measure the chest and the neck and use the chart as a tiebreaker.
Chest
Around the widest part of the rib cage, just behind the front legs, with the dog standing. Pull the tape snug, not tight.
Neck
Where a collar would sit, low on the neck. Deep-chested breeds often measure a size up in the chest and a size down in the neck.
Carriers
Length from nose to base of tail plus two inches, height from floor to top of head plus two inches. Airline carriers must also fit the airline's under-seat size, which varies.
