Stone Calculator
Decorative stone yardage and tonnage for any landscape
What is stone calculator?
A stone calculator answers the landscaper’s two questions on any decorative install: how many cubic yards do I need, and how does that map to tons for the delivery quote. The volume math (area times depth) is straightforward; landscape supply yards quote in tons, and density varies by stone type.
The default density is 95 lb/ft³, typical for general decorative landscape stone — a mix of natural granite, river-tumbled rock, or crushed quartz. Heavier basalt or limestone runs 100-110 lb/ft³; lava rock and pumice are much lighter at 50-70 lb/ft³. Volume math doesn’t change with stone type; only the tonnage readout does.
What depth to choose? Two inches works for refreshing existing stone beds. Three inches is the textbook minimum for first-time install over a fresh weed barrier — anything thinner won’t hide the fabric or suppress germinating weeds. Four inches is the right call for large stone (1.5 inches and up) because the larger the stone, the more void space between pieces and the less effective the visual coverage.
Bulk vs bagged: decorative stone is rarely sold in retail bag sizes for any project past a single planter. Landscape supply yards sell by the ton, typically ~$45-100 per ton delivered depending on stone type. Bulk wins on price and delivery for any bed past a few square feet.
The 10% waste factor default covers spread loss and minor over-fill at the edges. Bump to 15% for irregular bed shapes — curved or organic beds always burn through the overage faster than blocky rectangles. For mixed-size stone or rounded river rock, void space between stones reduces effective coverage; 15% is the safer choice there too.
When to use a stone calculator
- Decorative bed cover — Replace mulch with crushed or river stone in a permanent bed. Enter bed area and 2-3 inches depth for the order quantity.
- Dry creek bed feature — Naturalistic dry creek beds use mixed-size stone. The calculator handles average depth across the bed cross-section.
- Walkway edging and borders — Stone borders along sidewalks, beds, or driveways. Output in tons matches landscape supply pricing.
How to use the Stone Calculator
- Measure the area — For rectangular beds, multiply length by width. For winding paths or borders, multiply average width by total length. Curved beds: take three width measurements and average them.
- Pick a depth — Use 2-3 inches for decorative coverage; 3 inches is the textbook minimum for full weed suppression. Larger stone (1.5+ in) needs 3-4 inches because of void space between stones.
- Read the tonnage — Bulk decorative stone is sold by weight at landscape supply yards. Output shows tons (1 cu yd of decorative stone weighs roughly 1.28 tons at the default density).
- Apply waste factor — 10% covers spread loss and minor over-fill at edges. Bump to 15% for irregular bed shapes or mixed-size stone where void space eats into coverage.
Worked examples
300 ft^2 decorative bed at 3 in
Input: 20 ft x 15 ft x 3 in depth
Output: 2.78 cu yd / 3.96 tons (with 10% waste)Dry creek bed, 2 ft x 20 ft
Input: 2 ft x 20 ft x 4 in depth
Output: 0.49 cu yd / 0.71 tonsMixed-size river stone has more void space — order 15% extra.
Walkway border, 1 ft x 50 ft at 2 in
Input: 1 ft x 50 ft x 2 in depth
Output: 0.31 cu yd / 0.44 tons