How much ash does cremation produce?

Weight tells you almost nothing useful when you are buying an urn, because urns are not sold by weight. They are sold by capacity, measured in cubic inches, and the amount of space cremated remains occupy tracks the size of the person's skeleton rather than the weight of the ashes themselves.

The rule the funeral industry uses is one cubic inch of capacity per pound of body weight before cremation. Someone who weighed 160 pounds needs roughly 160 cubic inches. It is a generous rule, and it is nearly always enough.

They are not ash in the sense of what is left in a fireplace. Cremation reduces the body to bone fragments, which are then processed into a uniform, coarse, sand-like consistency. The color is usually pale grey or off-white, sometimes with a slight variation between one person and another.

Because what remains is skeletal, the amount is driven by bone density and frame size rather than by body fat. Two people of very different builds can produce a similar amount, and a taller person often produces more than a heavier but shorter one.

Adults typically fall in the three-to-seven-pound range, with men generally toward the upper end because of larger average bone mass. Older adults sometimes produce slightly less, as bone density declines with age.

Children and infants produce considerably less, sometimes only a few ounces. Families in that situation are usually looking at small keepsake vessels rather than a full-size urn, and it is worth asking the crematory or funeral director for the actual figure before choosing.

If you want the exact number for your own situation, ask. The crematory records the weight of the remains and will tell you.

Once you know roughly what capacity you need, sizing is straightforward. Full-size urns in our range hold 27.5, 55, 110, 165, 220 cubic inches, and each is named for the weight of the person it suits rather than the weight of the urn. The largest suits someone of about 200 pounds and holds 220 cubic inches.

Small keepsake vessels hold 6 to 10 cubic inches and are meant to hold a portion rather than all of it, which is what families choose when several people each want something to keep.

If you are between two sizes, go up. Extra capacity causes no problem at all, and the only mistake worth avoiding is choosing something clearly too small.