Choosing the right urn starts with understanding its capacity. A common guideline is that 1 cubic inch of urn space holds approximately 1 pound of body weight before cremation. For example, if your loved one weighed 180 pounds, an urn with a capacity of at least 180 cubic inches is typically recommended. https://www.yatskiaurns.com/blogs/news/how-much-ash-fits-in-an-urn