Landscape beds, paths, and borders
Rock Calculator
Size landscape rock for planting beds, garden paths, xeriscape, and borders. Convert coverage to cubic yards, tons, and bags — this calculator starts at pea gravel around 105 lb/ft³ and a typical 2.5-inch cover, not a 6-inch driveway.
Compaction and waste usually add 5–10%. Densities are bulk, not solid rock. Confirm with your supplier before placing a large order.
1.85 yd³ · 2.63 tons · $144
How to use
Measure the planting bed, border, or path you want to cover — not the whole yard. A rectangular bed is length times width. A tree ring is a circle: type the diameter and keep rock a few inches off the trunk. A border along a walk is length times the band width, usually 12–24 inches, not the width of the pavement beside it. If a landscape plan already lists square footage, switch that area to known area.
Depth is a decorative cover. Two inches over landscape fabric hides soil in a bed without burying plant crowns. Paths that will be walked on sit closer to 2.5–3 inches so gaps do not show after the stone settles. Xeriscape that replaces bark mulch is typically 2–3 inches. A typical starting depth is 2.5 inches for a mixed bed and path. Keep six-inch compacted depths for the gravel calculator; landscape rock is not a driving surface.
Choose a rock type so volume can turn into tons. Pea gravel, crushed stone, limestone, and marble chips cluster around 95–110 lb/ft³. Lava rock is about half that, so the same bed needs far fewer tons. Type a quarry density if the ticket lists tons per yard. Optional bag size and unit price help a short border; bulk by the ton or the yard is cheaper once you need about a cubic yard. This calculator does not add waste — order 5–10% extra for uneven ground, fabric wrinkles, and hungry edges.
How deep to lay landscape rock
Formulas
Coverage uses the same volume math as the gravel calculator. Density is what changes with the rock you order:
cubic feet = area (sq ft) × (depth in inches ÷ 12) cubic yards = cubic feet ÷ 27 tons = (cubic feet × density lb/ft³) ÷ 2,000
The sample 24×10 ft planting bed at 2.5 inches is 240 sq ft → 50 cubic feet → 1.85 yd³. Pea gravel at 105 lb/ft³ weighs 2.63 tons. The same bed of lava rock at 50 lb/ft³ is still 1.85 yd³ but only 1.25 tons. For circles, metric conversion, and more worked examples, see the formulas on the gravel calculator.
Landscape rock types and density
Use this calculator when you are ordering decorative landscape rock for beds, borders, xeriscape, or garden paths. Switch to the river rock calculator for rounded 1–3 inch cobble and dry creeks, or the gravel calculator for a driveway, patio base, or drainage trench.
| Material | Typical lb/ft³ | Default lb/ft³ | Tons / yd³ | Best for |
|---|---|---|---|---|
| Pea gravel | 100–110 lb/ft³ | 105 | 1.42 | Smooth 3/8 in stones for paths, play areas, and decorative beds. |
| Crushed stone | 100–120 lb/ft³ | 110 | 1.49 | Angular rock that locks together under compaction. |
| Limestone | 90–100 lb/ft³ | 95 | 1.28 | Lighter crushed limestone for patios and walkway bases. |
| River rock | 90–110 lb/ft³ | 100 | 1.35 | Rounded decorative stone; a pile looks heavier than it weighs. |
| Decomposed granite | 100–110 lb/ft³ | 105 | 1.42 | Fines pack into a firm path surface when moistened and rolled. |
| Lava rock | 40–60 lb/ft³ | 50 | 0.68 | Lightweight volcanic rock for xeriscape beds and decorative cover. |
| Marble chips | 90–105 lb/ft³ | 95 | 1.28 | White decorative chips for planting beds, borders, and accent color. |
Pea gravel is the small walking cover: comfortable underfoot, typically 105 lb/ft³, and it migrates on slopes unless you add an edge. Crushed stone and limestone are angular, so they stay put better in a bed or on a slight grade. Decomposed granite packs into a firm path when moistened and rolled — treat it as a surface, not as loose mulch. For a path, patio, dog run, or play area sized around pea gravel alone, use the pea gravel calculator.
Lava rock is much lighter than the other mixes. At about 50 lb/ft³ it is a lightweight xeriscape mulch: a cubic yard is only 0.68 tons, so a per-ton quote covers roughly twice the area of pea gravel. Marble chips sit near limestone at 95 lb/ft³ and are usually a color accent, not the cheapest way to fill a bed. A cubic yard of pea gravel is about 1.42 tons; the same yard of marble chips is 1.28 tons.
Rounded 1–3 inch cobble is sold as river rock. It is a cover, not a walking mix — use the river rock calculator so the density and depth match cobble, not pea gravel. Confirm color and size before the truck is loaded; decorative mixes vary more than crushed driveway stone.
Recommended landscape rock depth
Depth moves the order more than length or width. These ranges are starting points for beds, paths, and xeriscape — not for driveways or drainage trenches. Calculator presets apply 2 in decorative and 2.5 in path to every area; change any one area if part of the job is thinner.
| Use | Typical depth | Metric | Notes |
|---|---|---|---|
| Planting bed / border | 2 in | 5 cm | Hides soil over landscape fabric without burying plant crowns. |
| Garden path | 2.5–3 in | 6–8 cm | Comfortable underfoot; add an edge so small stone stays in the walk. |
| Xeriscape / mulch replacement | 2–3 in | 5–8 cm | Weed-suppressing cover in dry beds. Lava rock is much lighter per yard than stone chips. |
| Tree ring / circular bed | 2 in | 5 cm | Keep rock a few inches off the trunk. Enter diameter as a circle. |
Coverage quick-lookup
If you already know square footage, read across from your area. Each cell is cubic yards and US short tons at 105 lb/ft³ — the same pea-gravel density used above. Switch to lava rock for a much lighter ton result; cubic yards stay the same because volume does not depend on density.
| Area (sq ft) | 2 inyd³ / tons | 2.5 inyd³ / tons | 3 inyd³ / tons |
|---|---|---|---|
| 50 | 0.31 yd³0.44 t | 0.39 yd³0.55 t | 0.46 yd³0.66 t |
| 100 | 0.62 yd³0.87 t | 0.77 yd³1.09 t | 0.93 yd³1.31 t |
| 200 | 1.23 yd³1.75 t | 1.54 yd³2.19 t | 1.85 yd³2.63 t |
| 300 | 1.85 yd³2.63 t | 2.31 yd³3.28 t | 2.78 yd³3.94 t |
| 400 | 2.47 yd³3.50 t | 3.09 yd³4.38 t | 3.70 yd³5.25 t |
| 500 | 3.09 yd³4.38 t | 3.86 yd³5.47 t | 4.63 yd³6.56 t |
A 200 sq ft bed at 2.5 inches is 1.54 cubic yards and 2.19 tons of pea gravel — the same numbers as a 20 by 10 foot rectangle at this density. Double the depth and you double both cubic yards and tons. For a shape that is not in the table, type the measurements into the calculator. Add 5–10% extra when you order; the totals above are measured volume only.