Choosing the right size urn is the single most important decision you’ll make when memorializing a pet — too small, and it won’t hold all of the ashes; too large, and it can look out of place on a shelf. Here’s how to get it right the first time.
The 1-Cubic-Inch-Per-Pound Rule
Crematories and urn makers use a simple industry standard: allow approximately 1 cubic inch of urn capacity for every 1 pound of your pet’s body weight. This is an estimate, not an exact science — a pet’s ash volume can vary slightly based on bone density and body composition — but it’s accurate enough to guide your choice in nearly all cases.
Pet Urn Size Chart by Weight
| Pet Weight | Recommended Urn Capacity | Typical Urn Size Label |
|---|---|---|
| Under 20 lbs (cats & small dogs) | 20–25 cu in | Small |
| 20–50 lbs | 40–55 cu in | Medium |
| 50–90 lbs | 85–100 cu in | Large |
| 90–150 lbs | 130–160 cu in | Extra Large |
If your pet’s weight falls right on the border between two sizes, we recommend sizing up. An urn that’s slightly larger than needed is far less noticeable than one that’s too small to close properly.
What If You’re Not Sure of the Exact Weight?
Use your pet’s weight at a healthy adult stage rather than their weight at the time of passing, since illness can cause significant weight loss. If you’re still unsure, our team is happy to help — just reach out through our contact page with your pet’s breed and approximate size, and we’ll recommend the right fit.
Does Material Affect Sizing?
Not directly — a 50 cubic inch capacity holds the same volume whether the urn is solid walnut, ceramic, or biodegradable salt. What does change is how the urn is meant to be used: wood and ceramic urns are built for long-term display, while our biodegradable urns are designed to be buried or used in a water ceremony, so they’re generally offered in a narrower range of sizes suited to that purpose.
Frequently Asked Questions
What happens if I choose an urn that’s too small?
Some crematories will return ashes in a temporary bag alongside a display urn if the urn itself can’t hold the full volume. It’s best to size up if you’re unsure, or contact us before ordering.
Can one urn hold ashes for two pets?
Yes, as long as the combined weight fits the capacity guide above. Many families choose an Extra Large urn for two smaller pets who were companions.
Ready to find the right fit? Browse our full collection of pet urns, sized and labeled by weight for easy shopping.