What size urn does a rabbit or guinea pig need?
By the urn trade's rule of thumb, typical sizes are 12 cu in (cat); 70 cu in (dog)[1]. A rabbit or guinea pig needs a fraction of either. Here's how to size it right.
- Volume in cubic inches and millilitres
- Room left for keepsake urns
- Guidance on mini and keepsake urns
Urn size calculator
Enter your pet's healthy adult weight. We size the urn using the industry rule of 1 cubic inch per pound, plus 10% room to spare.
Recommended urn size
4.4 cu in (72 mL)
Look for: Small (up to 20 cu in)
| Total ashes (by volume) | 4 cu in (66 mL) |
|---|---|
| Expected ash weight | 1.9 oz–3.2 oz |
| Urn with 10% margin | 4.4 cu in (72 mL) |
Standard sizes: small up to 20, medium up to 60, large up to 120 and extra large 200+ cubic inches. If you're between sizes, choose the larger one.
Source: Embrace Pet Insurance - Bury or Cremate Your Dog? Costs, Pros & Cons; Our estimate. 1 cu in per lb is an industry rule of thumb
Next step: Find urns and prices near you →
Using the calculator
Three quick answers before you buy an urn
Enter your pet's weight, choose how many people will share the ashes, and say whether each person would like a keepsake urn of about 3 cubic inches. The calculator shows the main urn volume in cubic inches and millilitres, names the standard size band, estimates the ash weight and lists how much the keepsakes would take.
Most urn listings give capacity in cubic inches, sometimes in millilitres, and occasionally just in "pounds" of pet weight. The calculator's two units cover the first two; for the third, a listing that says "for pets up to 10 lb" is simply using the same one-cubic-inch-per-pound rule.
The rule of thumb
How the urn volume is worked out
The urn trade works on a simple rule: one cubic inch of space for every pound your pet weighed. The calculator adds a 10% margin so the lid closes easily over the bag or liner. Ashes themselves weigh about 3-5% of body weight[2], a pet-industry rule of thumb close to the roughly 3.5% found in a study of cremated remains, and the volume rule already allows for how loosely they settle.
Standard pet urns are sold in steps: small (about 20 cubic inches), medium (about 60), large (about 120) and extra large (200 and up). Even the smallest standard size is built for a cat or a small dog. For most rabbits and every guinea pig, the calculator will still label the result "small", the first band, so read a figure of a few cubic inches as keepsake or mini-urn size instead.
Worked examples
Urn sizes for rabbits, guinea pigs and ferrets
| Pet | Weight | Urn volume | Usually fits |
|---|---|---|---|
| Guinea pig | 1 kg (2.2 lb) | About 2.4 cu in (40 mL) | A keepsake urn |
| Chinchilla | 0.6 kg (1.3 lb) | About 1.5 cu in (25 mL) | A keepsake urn or locket box |
| Rabbit (medium) | 2.1 kg (4.6 lb) | About 5 cu in (83 mL) | A large keepsake or mini urn |
| Ferret (male) | 2 kg (4.4 lb) | About 5 cu in (80 mL) | A large keepsake or mini urn |
| Rabbit (giant breed) | 7 kg (15.4 lb) | About 17 cu in (280 mL) | A small standard urn |
Take a median pet rabbit. UK vet records put their adult bodyweight at about 2.1 kg, which is 4.6 lb. Add 10% and you need roughly 5 cubic inches. That's our estimate of about 74 g[3] of ashes, sitting comfortably in something the size of a large mug, not a standard 20 cubic inch urn with most of it empty.
Free tool
Ashes weight estimator
See roughly how much ash to expect back, by species and body weight.
Choosing the urn
What your result means when you're shopping
If your result is under about 3 cubic inches, look at keepsake urns, small wooden boxes or a heart urn. Between 3 and 10, a mini urn or larger keepsake works. Only giant rabbit breeds and the occasional very large ferret reach the small standard size. Going slightly bigger is fine if you'd like to add a fur clipping or a tiny note inside.
Price doesn't depend much on size at this end of the market. One industry report puts personalised urns at USD 50–1,000+[4], and a small, simple one can be very affordable. Our urn sizing guide for rabbits and guinea pigs compares materials, and the keepsakes and jewelry guide covers smaller pieces.
What would you most want to keep from your rabbit, guinea pig or ferret?
Tap an answer to vote and see how others answered. Anonymous.
Know the limits
What the urn calculator can't account for
Some providers return ashes in a bag inside a tin or tube, and that packaging takes space. If you plan to put the whole bag in the urn, go a size up. The calculator also can't know how finely the ashes were processed; finer ashes pack a little tighter.
If you're planning to bury the urn in the garden later, choose a biodegradable one and check local burial guidance, which our locations pages cover. If several people want a share, the ashes sharing planner shows how much each keepsake takes before you order.
Next steps
Ordering an urn without rushing
There's no need to have an urn ready before cremation. Most providers return ashes in a simple container you can keep them in for as long as you like. Many families wait until the first raw weeks have passed, then choose something that feels right. Our memorial ideas for small pets may help while you wait.
If you're still deciding between keeping the ashes and burying them, the aftercare options comparison lays out both side by side.
Want cremation options and urn suppliers in one reply? Send us your pet's details and we'll include both.
Reader polls
What would you choose?
Vote anonymously and see how other readers answered. The results are live counts from people who visit this site, so they show real opinions, not a scientific sample.
What would you most want to keep from your rabbit, guinea pig or ferret?
Tap an answer to vote and see how others answered. Anonymous.
Where are (or will be) your pet's ashes?
Tap an answer to vote and see how others answered. Anonymous.
What personal touch matters most on a memorial?
Tap an answer to vote and see how others answered. Anonymous.
Free tools to help you plan
Urn size calculator
Find the urn volume you need from your pet's weight, plus keepsake and sharing options.
Ashes weight estimator
See roughly how much ash to expect back, by species and body weight.
Ashes sharing planner
Split ashes fairly between family members, keepsake urns and jewelry.
Questions people ask
What size urn do I need for a guinea pig?
Usually around 2 to 3 cubic inches, or about 40 to 50 mL. That's the size of a typical keepsake urn. A standard small pet urn of 20 cubic inches would be mostly empty. If you'd like to include a fur clipping or a tiny note, go slightly bigger.
What size urn do I need for a rabbit?
Most pet rabbits need about 3 to 7 cubic inches, depending on breed. A 2 kg rabbit needs roughly 5 cubic inches, which is a large keepsake or mini urn. Giant breeds such as Flemish Giants, which can weigh 7 kg or more, may need a small standard urn of around 20 cubic inches.
Can I put two bonded rabbits' ashes in one urn?
Yes, and many families do. Add both rabbits' weights together and use that figure in the calculator. If the second rabbit is still alive, choose an urn with room for both, or a double-chamber urn, and keep the first set of ashes in their original container until then.
Is a keepsake urn big enough for all the ashes?
For many small pets, yes. Keepsake urns usually hold 1 to 5 cubic inches, which covers guinea pigs, chinchillas, hedgehogs and many smaller rabbits and ferrets. Check the stated capacity against the calculator's result before you buy, especially for larger rabbits.
Sources and our estimates
- [1] Using the industry rule of thumb of 1 cubic inch of urn space per pound of body weight, a 12 lb cat needs an urn of about 12 cubic inches; a 70 lb dog needs about 70 cubic inches. Our estimate: urn cu in = body weight lb x 1 (industry rule of thumb, not a measured value). How we calculate.
- [2] Embrace notes cremated remains typically weigh about 3-5% of the pet's original body weight. Embrace Pet Insurance - Bury or Cremate Your Dog? Costs, Pros & Cons, 2025.
- [3] A median-weight adult pet rabbit (2.1 kg) would be expected to return about 74 g (2.6 oz) of cremated remains. Our estimate: 2,100 g x 3.5%. How we calculate.
- [4] Personalized pet urns range from about USD 50 to more than USD 1,000. Astute Analytica via GlobeNewswire — Global Pet Preservation Services Market to Hit USD 112.7 Million by 2032 (Apr 2, 2024), 2024.
Get cremation and urn options together
Tell us what you need and where you are. We'll reply by email with clear options and prices so you can decide in your own time.