What Size Urn Do I Need? | Ashes & Urn Size Guide

Urn size guide: how much ash does an urn need to hold?

The right urn size depends on how much ash needs to be kept and what will happen to it. All of the ashes may be placed in one full-size urn, divided among family members, kept partly in a keepsake urn or ashes jewellery, buried in a cemetery plot, or placed in a columbarium niche with fixed dimensions.

When choosing an urn, always look at two things: the internal capacity and the external dimensions. Capacity tells you whether the urn can hold the ashes. External dimensions tell you whether the urn will fit in a niche, memorial cabinet, grave space or chosen place at home.

Quick answer: what size urn do I need?

Adult urn size: how much ash is left after cremation?

For one adult, the amount of ashes is often around 3 to 3.5 litres. In cubic inches, this is approximately 183 to 213 cu in. Many standard adult urns are designed around this capacity.

This does not mean every adult will leave exactly the same amount of ash. Ash volume is influenced more by skeletal structure and body composition than by body weight alone. A tall or strongly built person may leave more ashes than a smaller person. The crematorium can usually confirm the approximate volume after cremation.

If you want to keep all of the ashes in one urn, choose a full-size adult urn with enough internal capacity. If part of the ashes will be scattered or divided among relatives, the main urn may be smaller.

Litres and cubic inches: why both measurements matter

Urn capacity is often shown in litres, cubic inches or both. In practical terms, 1 litre is about 61 cubic inches. A standard adult urn of 3.5 litres therefore holds roughly 213 cu in.

Some countries use cubic inches as a practical capacity reference, while UK and Ireland families often find litres easier to compare. On this page, both measurements are shown where helpful. For a final choice, the actual ash volume from the crematorium remains the safest source.

Companion urns: one urn for two people

A companion urn is designed to hold the ashes of two adults. This is often chosen by partners who wish to remain together, or by families who prefer one shared memorial urn instead of two separate urns.

As a practical guide, a companion urn usually needs about twice the capacity of a standard adult urn. This means around 6 to 7 litres, depending on the amount of ashes and whether all ashes will be kept together.

Some families choose one large companion urn. Others choose two matching adult urns. If the urn will be placed in a columbarium niche, always check the niche dimensions before choosing a companion urn, because these urns can be too large for standard niches.

Keepsake urns, mini urns and ashes jewellery

A keepsake urn is used for a small portion of ashes. Families may choose keepsakes when the ashes are divided among relatives, when part of the ashes will be scattered, or when a main urn is placed in a cemetery while a small amount is kept at home.

Keepsake urns and mini urns do not need to hold all of the ashes. They usually hold a symbolic amount. Micro keepsakes and ashes jewellery hold even less, often just a small pinch or teaspoon of ashes, depending on the design.

If several family members want a keepsake, ask the crematorium or funeral director to separate the ashes before the main urn is sealed or interred. This is usually easier than doing it later.

Baby urns and child urns

Choosing an urn for a baby or child is especially sensitive. The required capacity depends on age, size and individual circumstances. For this reason, it is best to ask the crematorium or funeral director for the exact ash volume before ordering.

The table below is only a careful guide. It should not be treated as a fixed rule. Always use the information from the crematorium or funeral director if it is available.

Pet urn size: how to choose the right size

For pet urns, the size is usually based on the pet's weight before cremation. In this case, weight is a useful practical starting point. Larger dogs need much more urn capacity than cats or small pets.

The exact amount of ashes can still vary by pet crematorium and by the animal's body structure. If you are unsure, ask the pet crematorium before ordering.

Columbarium niche dimensions: capacity is not enough

If the urn will be placed in a columbarium, urn wall or niche, capacity is only part of the decision. The urn also has to fit inside the niche. A full-size adult urn may hold the ashes correctly but still be too tall, too wide or too deep for the available space.

Before buying an urn for a columbarium, ask the cemetery, crematorium or columbarium manager for the internal measurements:

• internal height;
• internal width;
• internal depth;
• whether the niche is for one urn or more than one;
• whether the front panel or plaque reduces the usable space;
• whether the urn must be a specific shape;
• whether keepsake urns or personal items may be placed inside.

If the niche is small, choose the urn by external measurements first and design second. This prevents the need to transfer ashes later.

Burial, scattering or keeping ashes at home

The destination of the ashes also affects urn size. If all ashes will be kept at home, a full-size urn is usually needed. If some ashes will be scattered and only part kept, a smaller urn may be suitable. If the ashes will be buried in a cemetery or placed in a memorial garden, the cemetery may have its own size and material requirements.

If you are planning burial or cemetery placement, ask about material, closure and permitted size before ordering. Some cemeteries prefer biodegradable urns for burial, while others allow ceramic, wood, stone or metal. Rules can differ by location.

When should you ask the crematorium or funeral director?

Ask the crematorium or funeral director if:

• you are not sure how much ash there will be;
• the person was very tall, small or strongly built;
• you are choosing an urn for a baby or child;
• you want to divide ashes among several family members;
• the urn will be placed in a columbarium niche;
• the ashes will be buried in a cemetery or churchyard;
• you are buying a custom-made urn before the ashes are available;
• you want to know whether the ashes will remain in a bag inside the urn.

It is better to ask before ordering than to discover later that the urn is too small or does not fit the intended place.

Common mistakes when choosing urn size

• Choosing by appearance without checking capacity.
• Forgetting that a columbarium niche has fixed dimensions.
• Assuming every adult urn holds the same amount.
• Buying a keepsake urn when all ashes need to be kept.
• Choosing a companion urn without checking the total ash volume.
• Not asking the crematorium for advice in baby, child or pet situations.
• Forgetting that cemetery rules may affect size and material.
• Confusing external dimensions with internal capacity.

Frequently asked questions about urn size

What size urn do I need for one adult?

For one adult, many full-size urns have a capacity of about 3 to 3.5 litres, or approximately 183 to 213 cu in. If you are unsure, ask the crematorium or funeral director.

How much ash is left after cremation?

For an adult, the average amount of ashes is often about 3 to 3.5 litres. The exact amount can vary because ash volume depends mainly on bone structure and individual circumstances.

What size is a companion urn?

A companion urn usually needs about 6 to 7 litres of capacity, or approximately 366 to 427 cu in, depending on the amount of ashes. This is roughly twice the capacity of a standard adult urn.

Can I use a keepsake urn for all ashes?

No. A keepsake urn is designed for a small symbolic portion of ashes. If you want to keep all ashes, choose a full-size urn with enough capacity.

Can I calculate urn size in pounds?

Yes. In the calculator above, pounds are first converted to kilograms. The recommendation is then based on the same practical weight-to-capacity table used for kilograms.

How do I choose a pet urn size?

For pets, use the pet's weight as a practical starting point. The pet table on this page can help you choose a suitable capacity. Ask the pet crematorium if you are unsure.

Does urn weight matter?

Capacity is more important than urn weight. The urn must have enough internal volume for the ashes. The physical weight of the urn itself mainly matters for handling, shipping or placement.

Can an urn be too large?

Yes, an urn can be larger than necessary. This is not always a problem if it will be kept at home, but it can matter for a niche, cabinet, grave space or memorial setting.

What if the ashes are still in a bag?

Many ashes are placed in a sealed bag before being put into an urn. Check whether the opening of the urn is large enough and whether the bag will fit comfortably inside.

Should I order before the cremation?

You can, but if the size is uncertain it may be better to ask the funeral director or crematorium first. This is especially important for children, babies, pets, columbarium niches and custom-made urns.

Useful links for choosing the right urn

Final thought: choose capacity first, then design

Choosing an urn is emotional, but the first step is practical: make sure the urn has enough capacity and fits the place where it will be kept. Once the size is correct, you can choose the material, shape, colour and style that feel right.

If all ashes will be kept together, choose a full-size adult urn or companion urn. If the ashes will be shared, add keepsake urns or ashes jewellery. If the urn will be placed in a niche, cemetery or memorial garden, check the measurements and rules before buying.