What Size Urn Do I Need For Human Ashes?

What size urn do I need to order?

To calculate the correct size urn for cremated remains you will use 1lb of the deceased weight equal to at least 1 cubic inch in the volume of the urn. The below calculator will help you calculate the size urn you need


1lb body weight = 1 cubic inch urn volume (approx 1 stone = 250ml)

This is a general rule with a couple of exceptions.

  1. If the deceased was particularly tall, you may need to add extra capacity.
  2. For stillborn and young babies you will also need to add slightly more for the capacity

Translated into imperial measures, the below table should help you decide the size of the urn you need. Typically, an urn for human ashes comes in 3-3.5 liters to hold the full remains and this will be suitable for 99% of cases.

Ashes Urn Size Guide

Urn Size for Human Ashes

Deceased Pre Death Weight
Cubic Inches / Litres
grams / kg
1lb / 0.072 stone / 0.45kg1 cubic inch / 17ml13 g
62lb / 4.5 stone / 28.5KG62 cubic inches / 1 Litre850 g
168lb / 12 stone / 76.2KG168 cubic inches / 2.8 Litres2.17 kg

Important Note: Height is also a contributing factor towards the total size you will need. Taller people will inherently have longer bones so there will be more ash. Fat is burnt away during the cremation process, so will have less of a bearing on the final amount of ashes. This should be taken into account when calculating the urn you will need. 

Cremation Ash Weight Calculator

How much do ashes weigh?

Human ashes weigh approximately 3.5% of the deceased body’s weight.

There are a number of factors that can alter this, but the industry rule of thumb is that the ashes will weigh approximately 3.5% of the body’s weight.

The calculation to find out how heavy cremated remains are looks like this:
Weight X 0.035 = Weight of Ashes

EG 168lbs x 0.035 = 5.88lbs in ashes
(168lbs = 12 stone)

Urn For Ashes Calculator

Calculating what size urn to order will be helpful to know before ordering, whether you are looking for an extra-large urn or maybe a small urn for ashes will determine the style, material, and look of the memorial you would like to purchase.