Lava Rock Calculator
Lava rock is so light — about half the weight of ordinary gravel — that tonnage-based gravel calculators overestimate what you need to buy. This lava rock calculator works in volume: cubic feet and yards for a landscape bed, or the fill for a gas fire pit or fire table burner pan.
What you'll need
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NUPICK 10lb Red Lava Rocks for Fire Pit, Volcanic Rock for Fireplace
$19.99
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HongWay 500 Pack 6 Inch Landscape Staples, Garden Staples Pins Galvanized 11 Gauge Ground Stakes Yard Lawn Staples for Turf Landscaping Fabric Fence Tent Irrigation Tube Outdoor Decorations
$37.99
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33ft. Galvanized Steel Landscape Edging (10-Pack) – 40" Metal Edging for Landscaping with 11 Stakes, Hammer-in Metal Landscaping Edging for Yard Pathway & Flower Beds – Lawn Edge for Garden Design
$69.99
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Black Lava Rocks for Fire Pit, Gas Fireplace Rocks, 1 to 2 Inch, 20 lbs
$47.44
View on Amazon →Prices as of Sep 25, 2026, 6:18 PM UTC. Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
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Frequently asked questions
- How much lava rock do I need for a fire pit?
- Measure the burner pan: a 36 inch round pan filled 4 inches deep needs about 2.4 cubic feet of lava rock, or five 10 lb bags. Keep 1 to 2 inches of rock over the burner itself.
- How much does a cubic yard of lava rock weigh?
- About 1,000 to 1,200 pounds, roughly half the weight of ordinary gravel. That is why lava rock is sold by volume, and why a gravel calculator that works in tons will overestimate it.
- How much area does a yard of lava rock cover?
- A cubic yard covers 162 square feet at 2 inches deep, 108 square feet at 3 inches, or 81 square feet at 4 inches — the same as any other material, because coverage depends on volume, not weight.
- Is lava rock good for landscaping?
- It is light, cheap to haul, holds its colour, and does not decompose. On the downside it can hold heat against plants in full sun and is sharp to handle. It works best in dry beds, around succulents, and as a mulch substitute in low-water gardens.
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