Urns are sold in many different sizes. Measurement's are calculated by the amount of ashes that each urn holds in Cubic Inches. One pound of pet weight equals one cubic inch of remains. Therefore, if your beloved pet weighed 17 lbs pounds you will need an urn that will hold at least 17 cubic inches. If you have any questions about what urn is best for your pet, please contact us at support@lifesongpetmemorials.com or 419-445-4200.