How to Find the Right Size Urn (Cubic Inch Rule + Quick Size Chart)

How to Find the Right Size Urn (Without Guessing)

Picking an urn can feel like a big decision. You want something that looks right, feels meaningful, and fits the space where it will be kept. But before you choose a style, there’s one practical question to answer first: will the urn hold the cremains comfortably?

The good news is that urn sizing is usually simple. Most urns are listed by internal capacity, measured in cubic inches. Once you know the capacity you need, you can shop with confidence.

This guide explains the sizing rule many families use, how to apply it for pets and people, and what to do in special situations like keepsake urns, sharing cremains, or scattering.

Urn Size Basics: Capacity Is What Matters

When people talk about “urn size,” they often mean the outside dimensions (height and width). But the number that matters most is the inside space, called capacity or volume.

Urn capacity is usually listed in cubic inches. Some brands may also list liters, but cubic inches is the most common measurement in urn listings.

Two urns can look the same on the outside and hold different amounts on the inside. That’s why the product description should include a capacity number. If you only see height and width, look for “capacity,” “volume,” or “holds up to” in the listing details.

The Simple Rule of Thumb for Urn Sizing

For most cremations, a dependable starting point is:

Choose an urn with about 1 cubic inch of capacity for every 1 pound of body weight before cremation.

Example: If a dog weighed 40 pounds, start with an urn that holds about 40 cubic inches.

This rule works well because cremains volume is usually related to body weight. It will not be exact every time, but it is accurate enough for most situations.

Why the rule isn’t always exact

Cremains can vary based on bone structure, body composition, and the cremation process. That’s normal. It’s also why many people prefer to size up slightly when they are between two options.

Quick Urn Size Chart Using the Cubic Inch Rule

If you want a fast reference, these examples use the same “1 cubic inch per pound” guideline. When you’re between sizes, choosing the next size up is usually the easiest way to avoid stress.

• 10 lb: about 10 cubic inches
• 25 lb: about 25 cubic inches
• 40 lb: about 40 cubic inches
• 60 lb: about 60 cubic inches
• 80 lb: about 80 cubic inches
• 100 lb: about 100 cubic inches
• 150 lb: about 150 cubic inches
• 200 lb: about 200 cubic inches

Remember, these numbers are about capacity, not the outside measurements. Always confirm the urn’s listed capacity before purchasing.

Step-by-Step: Finding the Right Size Urn for a Pet

If you’re choosing a pet urn, the process can be quick. Here’s a simple way to do it.

Step 1: Find your pet’s weight

Use your pet’s weight before cremation. If you have a recent vet record, that’s usually the best number to use. If you’re not sure, estimate as closely as you can.

Step 2: Match capacity to weight

Use the 1 cubic inch per pound rule as your baseline. Then decide if you want a little extra room.

• If you want a snug fit: choose a capacity close to the weight.
• If you want a little breathing room: go slightly larger, especially if you are between sizes.

Step 3: Check the product listing for “capacity”

Look for the capacity number in cubic inches. If the listing only shows dimensions, contact the seller or choose a listing that clearly states capacity.

Real-life pet sizing examples

These examples show how the math works. They are meant to help you picture the range.

• 10 lb cat or small dog: look for about 10 cubic inches (or a little higher).
• 25 lb dog: look for about 25 cubic inches.
• 50 lb dog: look for about 50 cubic inches.
• 80 lb dog: look for about 80 cubic inches.

If you’re torn between two sizes, choosing the larger capacity is usually the safer choice.

Step-by-Step: Finding the Right Size Urn for a Person

The same sizing rule can be used for a person’s urn: about 1 cubic inch per pound of body weight before cremation.

As a quick reference, many full-size adult urns are around 200 cubic inches. That’s because it fits many adults comfortably. But the best approach is still to use the person’s weight if you know it, then choose a capacity at or above that number.

If you do not know the person’s weight, the funeral home or crematory can often tell you what size urn is appropriate based on the container holding the cremains.

Keepsake Urns, Sharing, and “I Don’t Need to Hold Everything”

Not every urn is meant to hold all cremains. Many families choose to share cremains among several keepsakes, or keep a portion in a small urn while scattering the rest. In those cases, sizing works a little differently.

Keepsake urns

A keepsake urn is designed to hold a portion, not the full amount. Keepsake capacities vary widely. Some hold only a small amount, while others hold a more generous portion. Always check the listed capacity and choose based on how much you plan to keep.

If you are dividing cremains among multiple keepsakes, start by deciding how many portions you need, then choose capacities that make sense together. If you’re unsure, ask the crematory how much volume you’re working with and what portion sizes are realistic.

Companion urns (two pets or shared memorials)

A companion urn is meant to hold two sets of cremains in one urn. To size it, add the two weights together and use that total as the minimum capacity.

Example: Two dogs, 30 pounds and 45 pounds, would need at least 75 cubic inches of capacity. If you want a little extra room, you can size up from there.

Memorial boxes and room for keepsakes

Some people like to place small keepsakes with an urn, like a collar tag, a note, or a small photo. Not every urn is designed for this. A safer option is to choose a memorial box that has space for keepsakes, or choose an urn that is specifically built with an extra compartment.

If you want everything together and you are choosing a standard urn, it’s wise to avoid packing keepsakes into the main compartment unless the urn is designed for it. The main compartment is meant for the cremains container, and space can be tighter than it looks.

Scattering and Biodegradable Urns: Sizing Tips

Scattering urns and biodegradable urns still use capacity, but there are a few extra things to think about.

Scattering urns

Scattering urns are often shaped for easy carrying and pouring. If you plan to scatter all cremains, choose a scattering urn with full capacity (using the same sizing rule). If you plan to scatter only part, choose a smaller capacity that matches the portion you will scatter.

Biodegradable urns

Biodegradable urns are made to return to the earth over time. They may have thicker walls or a different shape than a traditional urn, but the capacity listing is still what you should follow. Focus on the capacity number, not the outside dimensions.

How to Compare Urn Sizes Online (So It Arrives the Way You Expect)

Shopping online is convenient, but it can also make sizes feel abstract. Here are practical ways to make sure you’re comparing the right details.

Look for these words in the listing

• Capacity or Volume (usually in cubic inches)
• Holds up to (often followed by a number of cubic inches)
• Full-size, keepsake, companion, or scattering

Know what “full-size” usually means

“Full-size” usually means the urn is designed to hold all cremains for one person or one pet. But it’s still important to confirm the listed capacity. “Full-size” is a category label, not a guarantee of a specific number.

When in doubt, choose the larger capacity

If you’re choosing between a 45 cubic inch urn and a 55 cubic inch urn for a 50-pound dog, the larger one is typically the safer choice. A little extra space does not hurt. Too little space is what causes problems.

Common Urn Sizing Mistakes to Avoid

• Choosing by height instead of capacity. A taller urn is not always a larger urn inside.
• Assuming all “medium” or “large” urns are the same. Always check the cubic-inch number.
• Forgetting about sharing. If you plan to use keepsakes, decide your plan before buying the main urn.
• Buying the exact minimum when you’re on the edge. When you’re between sizes, sizing up prevents stress later.
• Not asking the crematory for guidance when you’re unsure. They can often confirm the right capacity quickly.

FAQ: Urn Size Questions People Ask Most

What size urn do I need for a 60 lb dog?

A simple starting point is about 60 cubic inches of capacity. If you’re between sizes, it’s usually smart to go a little larger.

What size urn do I need for a 15 lb cat?

Start with about 15 cubic inches of capacity. Many families choose a slightly larger urn if they want extra room or prefer the look of a bigger style.

Is 1 cubic inch per pound always correct?

It’s a strong rule of thumb, not a perfect guarantee. Cremains volume can vary. If you want to be extra safe, choose a slightly larger capacity than the minimum.

Can I put a collar, tag, or note inside the urn too?

Some urns can, but many are designed to fit the cremains container snugly. If you want to keep items together, consider a memorial box, a companion keepsake, or an urn made with a separate compartment.

What if I don’t know the weight?

If you don’t know the weight, estimate as closely as you can, or ask your crematory or funeral home. They can often recommend an urn size based on the cremains container you will receive.

A Final Tip: Give Yourself Permission to Choose the Easy Option

When you’re making memorial decisions, the goal is not perfection. It’s peace of mind. Use the 1 cubic inch per pound rule to find a good starting point, confirm the capacity in the product listing, and size up slightly if you’re unsure. Once the sizing is handled, you can focus on what really matters: choosing an urn that feels like the right tribute.