What size urn does a hamster, rat or mouse need?
Urns for pets are sized for cats and dogs, and even the "small" ones hold around 20 cubic inches. A hamster's ashes fill less than half of one. This calculator shows the real volume so you can buy something that fits.
- Volume in cubic inches and milliliters
- Mini urn and vial suggestions
- Room for sharing between family
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
0.6 cu in (9 mL)
Look for: Small (up to 20 cu in)
| Total ashes (by volume) | 0.5 cu in (8 mL) |
|---|---|
| Expected ash weight | 0.24 oz–0.4 oz |
| Urn with 10% margin | 0.6 cu in (9 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. Very small pets can return only a spoonful of ashes, so a keepsake-sized urn is often enough.
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
Enter a weight, choose how many people, and check the result
- Enter your pet's weight in pounds or kilograms. The default is 0.5 lb, a sensible rodent middle point.
- Choose how many people will share the ashes, from one to eight.
- Tick keepsakes only if each person wants a keepsake urn. The tool allows about 3 cubic inches each, more than any rodent returns, so it will tell you the keepsakes hold everything.
The result shows the main container's volume in cubic inches and milliliters, the standard urn size band, the expected ash weight in ounces or grams, and the volume of any keepsakes. For rodents, the number that matters is the milliliters; it's the easiest to match against a vial or mini urn listing.
How it calculates
One cubic inch per pound, plus a little room
The industry rule of thumb is one cubic inch of urn space for every pound of body weight. The calculator adds a 10% margin so the lid closes easily. That rule sits comfortably with the finding that cremated remains weigh about 3-5% of body weight[1], close to the 3.5% average found in a study of 100 cremations; processed bone takes up a little less than a cubic inch per pound.
It then compares your volume with standard urn sizes: small (about 20 cubic inches), medium (60), large (120) and extra-large (200 or more). Every rodent lands in the "small" band, yet even a small urn is many times too big. For pets under 2 lb the tool adds a note that a keepsake-sized urn is often enough; in practice that means mini urns and vials, which typically hold between a few milliliters and a couple of cubic inches.
Worked examples
Three rodents, three very small containers
| Pet | Weight | Volume needed | Container that fits |
|---|---|---|---|
| Roborovski hamster | 25 g (0.06 lb) | Under 0.1 cu in, 1 mL | A tiny vial or single pendant |
| Syrian hamster | 150 g (0.33 lb) | About 0.4 cu in, 6 mL | A small glass vial or keepsake urn |
| Fancy rat | 500 g (1.1 lb) | About 1.2 cu in, 20 mL | A mini urn or small wooden box |
Rats are among the larger pets on this site at 350-650 g as adults, and they live 1.5-3 years[2], according to the Merck Veterinary Manual. Even so, a big buck rat needs less than two cubic inches. If you share a home with several rats over the years, a mini urn of three or four cubic inches can, if you wish, hold a whole group's ashes together.
What the result means
Choosing a container once you know the volume
One industry report puts personalized urns at about USD 50–1,000+[3], and another says urns account for 40%+[4] of pet memorial product revenue, so there's a lot on offer. For a rodent, three kinds of container make the most sense:
- Glass or metal vials with a screw or cork top: inexpensive and easy to display beside a photo.
- Mini keepsake urns in wood, ceramic or brass: large enough for a rat, with room for engraving.
- Cremation pendants: most hold only a pinch, about a twentieth of a cubic inch, ideal for a mouse's small return.
Many providers return ashes in a simple pouch or tube, and some will use a vial you bring. Our keepsakes and jewelry guide covers fill methods, and the ashes sharing planner shows how far the ashes stretch between people.
Free tool
Ashes sharing planner
Split ashes fairly between family members, keepsake urns and jewelry.
Being honest
What the urn calculator can't tell you
It assumes the provider recovers roughly the expected amount. For a mouse or dwarf hamster, a careless cremation can return less, and occasionally almost nothing. Confirm the likely amount with the ashes weight estimator and ask the provider before you order an engraved keepsake.
It also can't judge what feels right. Some families prefer an urn that's larger than needed, lined with a scrap of their pet's favorite fleece, because a tiny vial feels too small for how much they loved them. That's a good reason to size up, and the poll results show what other keepers chose to keep.
What would you most want to keep from your rat, hamster or mouse?
Tap an answer to vote and see how others answered. Anonymous.
Next steps
Before you buy a keepsake
Wait until the ashes are home, or at least until the provider has confirmed the amount. Then choose the container. If you're still deciding on aftercare, see all the options for tiny pets, check prices with the cremation cost calculator and our local pages, or send us your details to get exact prices near you.
If you'd like engraving, remember that mini urns have very little room. A name and two dates usually fit, though it isn't free: by our estimate, name-and-dates engraving adds about 36%[5] to the price of a mid-priced wooden pet urn; a longer line may need a small plaque or a card tucked beside the urn instead. Some families skip engraving entirely and pair a plain vial with a framed photo. Our memorial ideas for rodents has more ways to mark a small life without a large object.
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 rat, hamster or mouse?
Tap an answer to vote and see how others answered. Anonymous.
Which memorial feels most like your pet?
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.
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 hamster?
Well under one cubic inch. A 150-gram Syrian hamster needs about 6 mL of space, which fits in a small glass vial or keepsake urn. A dwarf hamster needs even less, about a milliliter. Any urn sold as "small" for pets will be much larger than necessary, which is fine only if you like the look.
Can I keep several rats' ashes in one urn?
Yes, if you're happy for them to be together. Each rat needs about one to two cubic inches, so a mini urn of four to six cubic inches holds several. Some owners use small separate bags inside one urn so each rat stays distinct, labeled with their name.
What does a cremation pendant hold?
Most hold roughly a twentieth of a cubic inch, which is less than a milliliter and about a pinch. That's enough for a small share of a hamster's ashes, or nearly all of a mouse's. Use a tiny funnel and fill it over a sheet of paper so nothing is lost.
Is it OK to use a household container instead of an urn?
Absolutely. A small jar, a lidded trinket box or a glass spice vial all work, as long as the lid seals well and the container won't break easily. Many families prefer something that was already part of their pet's life, like a wooden box that sat on the cage shelf.
Sources and our estimates
- [1] 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.
- [2] Pet rats live about 1.5-3 years and weigh 350-650 g as adults. Merck Veterinary Manual - Table: Rats at a Glance.
- [3] 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.
- [4] Pet urns generated over 40% of pet memorial product revenue in 2023. DataHorizzon Research — Pet Memorials Market report page, 2023.
- [5] Name-and-dates engraving adds about 36% to the price of a mid-priced wooden pet urn. Our estimate: midpoint engraving $32.50 ($25–$40) / midpoint wood urn $90 ($30–$150). How we calculate.
Get help choosing aftercare and a keepsake
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.