Stone Calculator
Decorative rock, river stone, lava rock, and crushed granite for landscape beds, borders, and xeriscaping. Yardage, tons, bag count, and landscape fabric estimate in one view.
How much decorative stone do I need?
Default: a 10 × 8 ft bed of river rock at 2.5 in depth.
What you'll need to buy
Prices approximate · Links go to retailer search results
- Decorative Landscape Stone — 0.5 cu ft bag0.5 cu ft
- Landscape Fabric — 3 x 100 ft
- Landscape Edging — 20 ft roll
Estimated total: ~$344 (materials, before tax)
Product links go to Home Depot search results — pick the best match for your project. Prices shown are rough averages.
How we calculated it
Decorative stone is a volume problem with a twist — different rock types have very different densities, so one cubic yard can be anywhere from 1,100 lbs (lava rock) to 3,100 lbs (crushed granite). This calc uses published industry densities to convert between yards and tons:
- River rock: ~95 lb/cu ft → ~2,560 lb/yd
- Mexican beach pebble: ~90 lb/cu ft → ~2,430 lb/yd
- Lava rock: ~40 lb/cu ft → ~1,080 lb/yd
- Crushed granite: ~110 lb/cu ft → ~2,970 lb/yd
- Pea gravel: ~96 lb/cu ft → ~2,590 lb/yd
- Marble chips: ~100 lb/cu ft → ~2,700 lb/yd
Decorative stone does not compact (unlike driveway aggregates) so loose volume = placed volume. The only reason to over-order is to handle settling, slope loss at edges, and spillage — 5-10% is plenty.
Frequently asked questions
How much decorative stone do I need for a 10x10 area?
A 10x10 bed (100 sq ft) at 2.5" depth of river rock is about 0.77 cu yd or ~0.75 tons. That is ~42 half-cubic-foot bags if you buy bagged. Depth matters a lot — 3" doubles the cost over 1.5".
What is the best depth for decorative stone?
2-3" for river rock and decorative pebbles in a landscaped bed. Deeper looks wasteful and is a trip hazard. Around pavers or in pathways, 1.5-2" is enough. Pure ground cover on landscape fabric can go as shallow as 1.5".
River rock vs pea gravel — which should I pick?
River rock (3-5" stones) is more decorative and stays put once placed. Pea gravel is smaller (3/8"), cheaper per yard, and easier to walk on but spreads out and gets tracked into nearby areas. For a modern zen-yard look pick river rock; for a budget path or playground fill, pea gravel.
How long does decorative stone last?
Decades. Unlike mulch, decorative stone does not decompose — river rock and crushed granite will still look the same in 20 years. The only maintenance is removing fallen leaves and occasionally pressure-washing if silt settles in.
Do I need landscape fabric under decorative stone?
Strongly recommended. Without fabric, soil slowly works its way up through the rock and weeds root in the accumulated soil. Use non-woven geotextile (the gray stuff), not the cheap black weed cloth — the latter rips and tangles in root systems.
Can I put decorative stone around my house foundation?
Yes, and it is actually better than mulch for foundations. Stone does not attract termites, does not retain moisture against the foundation, and does not need replacing. Slope it away from the foundation and keep the top of the stone 4-6" below any siding or weep holes.
Is white / light stone harder to keep clean?
Yes — white marble chips or light granite shows organic staining (tannins from tree leaves, algae, mulch leaching from adjacent beds) within 1-2 years. If the bed is under trees or near mulched beds, pick a mid-tone crushed granite or pea gravel instead.
How heavy is a yard of decorative stone?
About 2,400-2,800 lbs per yard for river rock, 2,200-2,500 for pea gravel, 2,900-3,100 for crushed granite. Lava rock is a notable exception at ~1,100 lbs/yd — the weight is why lava is cheaper to ship but needs more volume for the same visual depth.
Can I mix mulch and stone in the same bed?
You can, but install a metal or stone edging between them — mulch crumbs migrate into rock and look messy, and stone settles into mulch over time. Most landscapers use stone as a border ring around tree rings or walkways and mulch in the plant beds.
How do I calculate stone for an irregular bed?
Break the shape into rectangles or semicircles and add the sub-areas. For example, a curved border: estimate the longest dimension × average width. If wildly irregular, measure the bed footprint with a rope and calculate sq ft by breaking it into blocks. Always round up on the waste factor — 10% minimum, 15% if the border is windy.