Pet Urn Size Guide: Cubic Inches by Pet Weight
A pet needs roughly one cubic inch of urn space per pound of body weight. Add 25% for the ash bag and lining, then compare that figure with the interior dimensions — a "medium" box from one supplier can hold more than a "large" box from another. Below is the conversion table, the interior capacity of every urn we produce, and the sizes crematories reorder most.
How urn capacity is calculated
Interior capacity is geometry, not a marketing label. A rectangular box is length × width × height, a round urn is πr²h, and both are converted to litres at 1 cu in = 0.0163871 L. The numbers on this page come from the actual interior dimensions in our product specs, so a buyer can verify them with a tape measure before ordering.
Step 1 — weight in pounds
Use the vet-recorded weight. Breed averages miss individual dogs by 10–20 lbs in either direction.
Step 2 — convert to cubic inches
One pound of body weight produces roughly one cubic inch of cremated ash. A 60 lb dog plans for 60 cu in.
Step 3 — add 25% headroom
The ash bag, velvet lining and lid seal take real space. Order a box with at least 1.25× the calculated volume.
Pet weight to urn capacity
Minimum ash volume by body weight. This is the floor, not the target — order above it for headroom.
| Pet weight | Ash volume (cu in) | Ash volume (litres) | Typical pet |
|---|---|---|---|
| Up to 10 lbs | 10 cu in | 0.16 L | Cat, small terrier |
| Up to 25 lbs | 25 cu in | 0.41 L | Cocker Spaniel, large cat |
| Up to 50 lbs | 50 cu in | 0.82 L | Border Collie, Labrador puppy |
| Up to 75 lbs | 75 cu in | 1.23 L | Labrador, Golden Retriever |
| Up to 100 lbs | 100 cu in | 1.64 L | German Shepherd |
| Up to 125 lbs | 125 cu in | 2.05 L | Large breed, two small pets |
Interior capacity of our wooden urns
Calculated from interior dimensions. Comfortable capacity assumes 75% usable space once the bag and lining are fitted.
| Product | Inner size | Shape | Interior | Comfortable | Fits |
|---|---|---|---|---|---|
| House Shape Urn (6"×4"×8") | 6" × 4" × 8" | Rectangular box | 192 cu in / 3.15 L | 144 cu in | Up to 50 lbs |
| Square Urn (7"×5"×10") | 7" × 5" × 10" | Rectangular box | 350 cu in / 5.74 L | 262 cu in | Up to 100 lbs |
| Rectangular Urn (9"×6"×4.5") | 9" × 6" × 4.5" | Flat rectangular box | 243 cu in / 3.98 L | 182 cu in | Up to 120 lbs |
| Round Urn (Ø5" × 7") | 5" dia × 7" height | Cylinder | 137 cu in / 2.25 L | 103 cu in | Up to 40 lbs |
| Walnut Cremation Box (8"×5"×10") | 8" × 5" × 10" | Rectangular box | 400 cu in / 6.55 L | 300 cu in | Up to 120 lbs |
| Oak Memorial Urn (7.5"×5.5"×10") | 7.5" × 5.5" × 10" | Rectangular box | 412 cu in / 6.76 L | 309 cu in | Up to 110 lbs |
| Bamboo Urn (6"×4.5"×8") | 6" × 4.5" × 8" | Rectangular box | 216 cu in / 3.54 L | 162 cu in | Up to 55 lbs |
| Mini Keepsake (2"×2"×1.5") | 2" × 2" × 1.5" | Small keepsake box | 6 cu in / 0.10 L | 4 cu in | Symbolic share only |
| Heart Shape Urn (5"×4.5"×3") | 5" × 4.5" × 3" | Heart box | 68 cu in / 1.11 L | 51 cu in | Up to 25 lbs |
| White Painted Urn (6"×4"×8") | 6" × 4" × 8" | Rectangular box with frame | 192 cu in / 3.15 L | 144 cu in | Up to 50 lbs |
| Mini Walnut Keepsake (1.8"×1.8"×1.3") | 1.8" × 1.8" × 1.3" | Small keepsake box | 4 cu in / 0.07 L | 3 cu in | Symbolic share only |
| Mini Heart Keepsake (2.5"×2.5"×1") | 2.5" × 2.5" × 1" | Small heart keepsake | 6 cu in / 0.10 L | 5 cu in | Symbolic share only |
| Glazed Ceramic Urn (Ø5" × 8") | 5" dia × 8" height | Cylinder | 157 cu in / 2.57 L | 118 cu in | Up to 60 lbs |
| Matte Ceramic Urn (Ø4.5" × 7") | 4.5" dia × 7" height | Cylinder | 111 cu in / 1.82 L | 84 cu in | Up to 35 lbs |
| Brass Metal Urn (Ø4" × 7") | 4" dia × 7" height | Cylinder | 88 cu in / 1.44 L | 66 cu in | Up to 30 lbs |
| Plant Fiber Urn (7"×5"×5") | 7" × 5" × 5" | Moulded rectangular box | 175 cu in / 2.87 L | 131 cu in | Up to 60 lbs |
| Scattering Tube (Ø3" × 12") | 3" dia × 12" height | Cylinder | 85 cu in / 1.39 L | 64 cu in | Up to 40 lbs |
| Memory Box Set (10"×8"×4") | 10" × 8" × 4" | Rectangular box | 320 cu in / 5.24 L | 240 cu in | Up to 110 lbs |
| Photo Frame Ash Drawer (5"×4"×1.5") | 5" × 4" × 1.5" | Keepsake drawer | 30 cu in / 0.49 L | 22 cu in | Keepsake portion only |
| Walnut Frame Drawer (6"×5"×1.5") | 6" × 5" × 1.5" | Keepsake drawer | 45 cu in / 0.74 L | 34 cu in | Keepsake portion only |
| Paw Charm Chamber (0.5"×0.5"×0.3") | 0.5" × 0.5" × 0.3" | Jewelry chamber | 0.1 cu in / under 0.01 L | 0 cu in | About 1 ml, symbolic |
| Ash Pendant Chamber (0.8"×0.8"×0.4") | 0.8" × 0.8" × 0.4" | Jewelry chamber | 0.26 cu in / under 0.01 L | 0 cu in | About 4 ml, symbolic |
Cremation caskets are excluded from this table: they hold the pet before cremation, not the ashes afterwards. See paulownia caskets.
Four steps to the right size
- 1
Weigh the pet, not the breed
Use the last recorded weight from your vet. Breed averages overshoot small individuals and undershoot large ones by 10–20 lbs.
- 2
Multiply pounds by 1 cubic inch
A 60 lb dog needs roughly 60 cu in of ash space. Add 25% headroom for the bag, lining and sealing gasket.
- 3
Match to inner dimensions, not the product name
Our "medium" is defined by inner size, not by weight. Check the table above — the same 192 cu in box appears under several product names.
- 4
Confirm the lid style you need
Screw-down, sliding or hinged lids change usable height by 0.5"–1". If you need a photo panel inside the lid, subtract its depth.
Four sizing mistakes that turn into returns
Buying by product name instead of cubic inches
A "large" box from one supplier can hold less than a "medium" from another. Always compare interior volume.
Forgetting the bag and lining
A velvet lining plus the ash bag can take 20–25% of the interior volume. Size up when both are specified.
Splitting ashes without planning the keepsake count
Four family members usually means four keepsakes. Order keepsakes with the main urn so the batch matches in colour and grain.
Using a cremation casket as a permanent urn
Paulownia caskets are built for viewing and cremation. They are far larger than needed and not sealed for long-term ash storage.
Size by breed
Typical adult weight ranges. Individuals vary — weigh your own pet before ordering.
| Breed | Typical weight | Recommended urn |
|---|---|---|
| Domestic shorthair cat | 8–12 lbs | Small / Heart shape |
| Maine Coon | 12–18 lbs | Small / Heart shape |
| Yorkshire Terrier | 4–7 lbs | Mini keepsake (symbolic) |
| Miniature Schnauzer | 11–18 lbs | Small / Heart shape |
| Cocker Spaniel | 20–30 lbs | House shape (medium) |
| Border Collie | 30–45 lbs | House shape (medium) |
| Labrador Retriever | 55–80 lbs | Square or Walnut box |
| Golden Retriever | 55–75 lbs | Square or Walnut box |
| German Shepherd | 60–90 lbs | Square or Walnut box |
| Great Dane | 100–175 lbs | Rectangular flat box |
Urn sizing questions
How do I work out what size pet urn I need?
Weigh the pet, then allow roughly one cubic inch of ash space per pound of body weight. Add 25% headroom for the ash bag and lining, then compare that number with the urn inner dimensions — not the product name.
Does a 50 lb dog need exactly 50 cubic inches?
About 50 cu in is the ash volume to plan for. A 192 cu in box such as our house-shape urn leaves a comfortable margin, because the interior volume is larger than the ash actually occupies.
What is the difference between a keepsake urn and a full urn?
A keepsake holds a symbolic share — our mini boxes hold roughly 4–6 cu in — while a full urn holds the entire set of ashes. Keepsakes are sold alongside the main urn, usually one per family member.
Do the listed cubic inches include the bag and lining?
No. The cubic inch figure is the raw interior volume. Plan on 70%–80% usable space once the ash bag, velvet lining and lid seal are in place.
Can two pets share one urn?
Yes, if the combined ash volume fits with headroom. Add both weights, convert to cubic inches and allow 25% extra. Most shared urns are the flat rectangular or square shapes, which keep the surface area large enough for two engravings.
Which urn size sells best for crematories and clinics?
The medium house-shape urn at 192 cu in covers cats through 50 lb pets and is the volume most crematories reorder. Large square urns at 350 cu in cover 50–100 lb dogs, and mini keepsakes are the add-on that lifts order value.
Need a size we do not stock?
Interior dimensions are cut on a CNC line, so a custom size is a tooling change rather than a new product line. Send the interior volume you need and the destination market — we reply with price tiers at 50 / 200 / 500 pcs and lead time.