Start with the exact item
Different harnesses and collars use different measurement points and adjustment ranges. Read the instructions and size chart for the specific item you are considering.
Record the relevant measurements
Use a flexible tape and note neck and chest measurements where the item instructions specify. Record the unit and measurement date so the numbers keep their meaning.
Compare, then ask
Compare with the exact item chart rather than using breed or a letter size alone. Ask about adjustment, putting the item on and what to check during a fit assessment.
Keep the note handy
Use Dog measurements to keep a local record. The tool does not choose a size or certify a safe fit. Share the note with an enquiry only when you choose to include it.