As you’re shopping around for a memorial urn, you might realize that there are quite a few different urn sizes.
How do you know what size urn you need?
Here’s our guide to urn sizes – inside, outside, and for all types and purposes. Read on to learn everything you need to know to choose the right sized urn.
What is the standard size of an urn?
The standard urn size is 200 cubic inches of interior capacity.
Outside dimensions of urns vary considerably depending on shape and design. A rounded, vaseshaped vessel with ornate lid and a simple wooden box might both be a standard size of 200 cubic inches, but have vastly different exterior measurements.
How do I know what size urn to buy?
There are two ways to talk about the size of the urn: The inside, meaning the capacity or volume, or the outside, meaning the external measurements.
Urn Size: Capacity
This will help you decide how much space you need inside the urn.
You need a cremation urn that has a larger interior capacity than the amount of cremated remains or “ashes” that you have.
Too much space is fine; you can always have it halffull or add in some meaningful mementos or keepsakes. What you want to avoid is too little space.
Cremation urns are measured in cubic inches. Nearly all urn product details sections will list the cubic inch volume of the urn.
Typically, for an adult human, you will need an urn with an inside capacity in cubic inches equal to or greater than the individual’s weight in pounds. For most adults, an urn with a standard 200 cubic inch size will do just fine.
Urn Size: Dimensions/Measurements
This will help you decide how much space the urn can take up.
You also need an urn that will fit where you need it to go. If it’s being buried, it will need to fit into the burial vault. For a columbarium, you will need it to fit into the niche.
Even if you’re keeping the urn at home, you’ll still want it to fit on the shelf, not be too big or small for the table, fit into the hutch, and so on.
So the exterior measurements are important. But most of the time, when people talk about urn sizes, they’re talking about capacity and whether or not the ashes will fit into the urn.
Let’s figure out what you need.
Urn Size Calculator
Use this simple calculator for a quick estimate of the capacity you’ll need in cubic inches.
Loved One’s Total Weight in Pounds  
Remains in Cups (to help you visualize)


Typical Urn Size Needed in Cubic Inches  
1 Pound = 1 Cubic Inch
1 Cup = 14.44 Cubic Inches

Please note that there are more variables involved, and the total amount of ashes it typically less than 200 cubic inches. Read on for more specific information.
How many cubic inches of ashes will there be?
The amount of ashes, or “cremains”, that each urn holds is measured in cubic inches. The industry standard is approximately 1 pound of healthy weight to 1 cubic inch of cremains; that is, a 180lb person will require roughly 180 cubic inches.
Most adult cremation urns will hold 200 cubic inches at a minimum, and some hold more. We always list the cubic inches that each urn will hold in the product description for each of our urns.
For a larger individual, the measurements can be a little tricky. The “cremains” are composed of the bone matter that remains after the cremation process. This means that regardless of a person’s actual weight, the cremated remains should be around the same amount as the average person of the same height.
Here is a handy chart to help you figure weight based on height.
Of course, there are variations in bone density and structure, so for a larger individual, it is wise to err on the side of more cubic inches. Often, families will choose a companion urn, which usually hold 400 cubic inches.
Urn Sizes
Typically, urns come in several main sizes. Here are the most important ones to know.
Standard Adult Urns
Most urns that you find will either say “adult” or “standard” or simply “urn” without any size modifier. For most urns for humans, the typical size has a capacity of 200 cubic inches.
Companion Size Urns
Some couples choose a companion urn as a way to signify that they will be “together, forever.” These urns typically will hold 400 or more cubic inches, and can often be made with or without separate compartments inside.
If you choose an urn with a divider or two separate compartments, then both sides will be roughly 200 cubic inches. Again, be sure to see the details on each product page, and use the same calculations as above to determine if the urn will be suitable.
Keepsake Urns
Keepsakes urns vary widely in size; some hold as little as 1 cubic inch of remains, while others hold up to 100 cubic inches. Choose your keepsake urn carefully depending on its intended usage.
If you would like to divide the remains among several relatives, it is usually best to get several 50+ cubic inch keepsake urns.
Pet Urn Sizes
Pet cremation urns vary quite a bit. There’s no standard capacity or size for pet urns.
This is because there are cats and small dogs all the way up to large dog breeds like Great Danes and Newfoundlands. For some of these, a 10 cubic inch urn will suffice. For others, say an English Mastiff, you might need a 300 or even 400 cubic inch urn.
Typically, you’ll find pet urns ranging in size from 10 or 20 cubic inches up to 200 cubic inches. To figure out what size urn for your dog, cat, or other pet, use the same rule of thumb: 1 lbs body weight will approximately equal 1 cubic inch of cremation ashes.
Other Sizes
Less common sizes for urns are simply measured in cubic inches. For urns less than 200 cubic inches, these will often be described as small, extra small, child, or pet sized urns. Urns larger than 200 cubic inches are described as large, extra large, double, or companion urns.
Here are many of the sizes you’ll find, in cubic inches. In parenthesis is how they are described (large, medium, etc) and the intended use (pet, adult, etc). The bold ones are the most common.
 Between 150 cubic inches (small; keepsake)
 50 cubic inches (small; pet)
 100 cubic inches (medium; pet)
 150 cubic inches (medium)
 200 cubic inches (standard; adult; rarely: large)
 250 cubic inches (extra large, large capacity)
 300 cubic inches (extra large)
 350 cubic inches (extra large; companion)
 400 cubic inches (companion)
What If I’m Still Unsure?
If you’re still not sure what size or type of urn you need, or whether a particular urn will work for your situation, please contact our customer service team at Urns Northwest and we’ll be happy to help you.