Multiply length × width in feet by depth in feet, divide by 27 for cubic yards, then multiply by 1.35 for tons of marble chips. A 15 × 10 ft bed at 2 inches deep needs about 0.93 cubic yards — roughly 1.25 tons. Lava rock weighs less than half as much, so the same bed takes only about 0.6 tons.
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Order – tons (includes your waste allowance) so compaction and spillage don’t leave you short.
Decorative Stone Calculator Guide
Decorative stone is bought with the eyes and paid for by the ton — which makes it the category where a density mistake shows up largest on the invoice. A bed sized for marble chips at 1.35 tons per cubic yard needs less than half that tonnage in lava rock, and the calculator reflects whichever material you select. Choose the look first; the arithmetic follows the stone.
Because decorative layers are shallow — two inches is the standard — small beds come out to surprisingly small tonnages. Resist the urge to round a 1.2-ton answer up to two full tons: decorative products carry the highest per-ton prices in the yard, and surplus show-stone has fewer uses than surplus base rock.
Which Decorative Stone Covers the Most per Ton?
All coverage figures below are for a 2-inch layer. The lighter the stone, the further a ton stretches:
| Stone | Tons per yd³ | 1 ton covers | The look |
|---|---|---|---|
| Lava rock | 0.65 | 249 sq ft | Deep red-black, porous, matte |
| Marble chips | 1.35 | 120 sq ft | Bright white with crystalline sparkle |
| Pea gravel | 1.35 | 120 sq ft | Warm mixed earth tones, rounded |
| Decomposed granite | 1.40 | 116 sq ft | Tan-gold fines, natural trail feel |
| River rock | 1.50 | 108 sq ft | Smooth gray-blue rounded stones |
Design Choices That Decide the Order
- Match stone size to bed scale: chips under an inch suit tight borders and container mulch; 1–3 inch stones read better across wide beds.
- Contrast with the house, not the plants: white chips pop against dark siding but can glare in full sun; lava rock warms gray facades.
- Edge every bed: steel, aluminum, or paver edging is what keeps a crisp line between stone colors — without it, materials migrate and mix within a year.
- Fabric underneath, always: decorative stone is a long-term surface, and pulling weeds through rock is miserable enough to justify the membrane.
- Buy one bag before the bulk load: stone color varies by quarry lot; audition a sample against your siding in daylight before committing to tons.
For deeper dives into the two most popular decorative materials, the river rock calculator covers sizing rounded stone, and the pea gravel calculator handles the classic path-and-patio filler.
Frequently Asked Questions
How much does a ton of decorative stone cover?
At 2 inches deep: marble chips and pea gravel cover about 120 square feet per ton, river rock about 108, and featherweight lava rock stretches to roughly 249 square feet. Density is the whole difference — coverage per cubic yard is identical.
Do white marble chips stay white?
Largely yes — marble does not fade the way dyed products can. They do collect dust and organic film, so an occasional hose-down keeps the sparkle, and siting them away from heavy leaf drop reduces staining.
Why choose lava rock over heavier stone?
At about 0.65 tons per cubic yard, lava rock is the easiest decorative stone to haul and spread — a ton covers nearly 250 square feet at 2 inches. Its porous structure also insulates soil against temperature swings, though it can crush underfoot in walkways.
How deep should decorative stone beds be?
Two inches for chips and small stones under an inch across, three inches for stones in the 1–3 inch range. Any deeper wastes material; any shallower lets fabric or soil peek through within a season.