Lava Rock Calculator

How much lava rock do I need?

ft
ft
in

Order this much lava rock

1.25cubic yards

Includes 5% extra, rounded up to the nearest quarter yard. Weight varies a lot by source rock, so ask your yard for a figure.

20 ft6 ft0"3"6"9"12"
Exact volume30 cu ft
0.5 cu ft bags63
Typical weight0.6 to 0.9 tons
Half-ton pickup trips2

Lava rock is light and porous, so a yard goes further on the truck than gravel. Enter your bed for yards, bags and a realistic weight range.

How it works

Length × width × depth converted to cubic yards with 5% added. Weight is shown as a range of about 0.5 to 0.75 tons per yard because sources vary.

Before you order

  • Plan about 2 to 3 inches deep over fabric so the soil does not show through.
  • Wear gloves, since the edges are sharp enough to scrape skin.
  • Avoid high-traffic areas, as lava rock crushes and sheds grit under foot.

Common questions

How much does a yard of lava rock weigh?

Published figures run from about 1,000 to 1,500 lb per cubic yard, well under the weight of ordinary gravel.

Does lava rock need fabric underneath?

Fabric keeps rock from sinking into soil and makes later cleanup easier.