The general rule is that the weight in Pounds (lbs) before cremation equals Cubic Inches in ashes. For example: If the weight was 60-225 lbs = Adult Urn (up to 225 cubic inches) If the weight was 30-60 lbs = Medium/Child Urn (up to 60 cubic inches) For dividing remains or small mementos = Keepsake/Tealight Urn (up to 30 cubic inches)