How much is a large urn for ashes?

Hi, we're going to need a large urn for someone in my family was obese and they passed away from an accidental insulin overdose the other day. The family proceeded to point out different roles for the funeral arrangement and I was appointed with having to make arrangements for cremation and an urn. I have no idea what size urn I should be getting, I think he was about 200lb? Thanks in advance!