How to Choose a Cremation Urn Size

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Guest Blog
February 7th 2024 - 5 minute read
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This cremation urn guide helps you choose an urn size and tells you what to expect from different types of urns.

When choosing a cremation urn, many options and customizations are available to families. However, one of the most critical aspects of an urn is ensuring that it will hold the deceased's ashes. To help you determine this, we have provided a guide on choosing an urn size and what you can expect from different types of urns.

Determining urn size


Urns often come in a standard size capable of holding the average volume of ashes from an adult cremation. However, this can vary depending on type and design. Therefore, to ensure you are getting the right size, you can follow this general guideline.

Before cremation, each pound (or half a kilogram) of body weight equals approximately one cubic inch (16.3 cubic cm) of ashes. If someone was 175 lbs (79.4 kg) before cremation, they would need an urn with a capacity of at least 175 cubic inches (2868 cubic cm or 2.8 litres). However, this can vary slightly depending on the type of cremation chosen.

Aquamation, for example, creates approximately 20 to 30 per cent more ashes than flame cremation. Therefore, if choosing aquamation, it is essential to factor this into the urn selection process.

How to choose an adult urns

Adult urns come in a variety of sizes, styles, and materials. Most standard ones are created with the capacity to carry the ashes from anyone up to around 200 lbs (91 kg) in body mass. Based on the calculation mentioned above, this would mean that most adult urns have a capacity of at least 200 cubic inches. However, sizes often will range from 150 to 250 cubic inches. Smaller and larger sizes may also be available on request.

The standard urn sizing will often work well for those choosing aquamation. Still, it is important to note the slight capacity differences. For example, an individual weighing 150 lbs (68 kg) will create enough ashes to fill a capacity of approximately 150 cubic inches. However, through aquamation, the same individual would make enough ashes to fill a total of 180 to 195 cubic inches. Therefore, someone weighing more may need an urn with a larger capacity.

Eirene offers a variety of adult-sized urns on our website. In addition, you can browse our extensive urn catalog here.

How to choose an infant urns

Infant urns hold the remains of an infant that has died. These are typically smaller in capacity and display a theme related to children. Infant urns will often range from 5 to 70 cubic inches. In addition to ashes, these urns sometimes store other objects to remember the deceased, such as a lock of hair or dirt from a gravesite.

The term infant generally refers to children from birth to 1 year old. The weight range for infants varies greatly depending on age, sex, and other conditions, but on average will be anywhere from 7 lbs (3.2 kg) to over 20 lbs (9 kg). Therefore, there is no standard quantity of ashes produced during the cremation process. However, the guideline can be used to get a general idea of what capacity is needed.  You can also use this article as a reference guide.

Based on the range, with flame cremation, an urn with a capacity of approximately 7 to over 20 cubic inches is needed. With aquamation, an urn with a capacity of roughly 10 to 26 cubic inches is required.

Eirene sells a variety of infant ashes in many sizes and style options. Prices range from $100 to $600 (click for our infant urns).

What is a companion urn for?

A companion urn stores the cremated remains of two people. Some versions have a single compartment, where remains are mixed. Others have a double-compartment, allowing the remains to be together but separated.

As mentioned above, most single adult urns will have the capacity to carry ashes from anyone around 200 lbs (91 kg). In most cases, companion urns double this capacity. Therefore, the standard size for one is typically 400 cubic inches.

With flame cremation, two individuals weighing 175 lbs (79.4 kg) would need a capacity of approximately 350 cubic inches. In contrast, aquamation would need a capacity of 420 to 456 cubic inches. Therefore, the standard companion urn size may not hold both ashes. Again, this is important to consider during urn selection.

You can find a great selection of companion urns on the Eirene store website. Prices range from $400 to $1,400 - see them here: companion urns).

Looking for a small urn or specialty urn?

See our guide to small cremation urns such as tealight urns, micro urns , mini urns and keepsake urns: click here.