Landscape Rock Calculator
A landscape rock calculator turns bed size and depth into tons at 1.4 tons per cubic yard: a 15 × 10 ft bed at 2 in needs 1.30 tons, or 1.43 with extra.
What your order looks like
A few bags or one pickup trip will cover it.
0.93 yd³ · 1.3 tons
13 wheelbarrow trips (2 cu ft each)
2 pickup loads (0.75 ton each)
1 small dump truck load (6 tons each)
Rules of thumb: A wheelbarrow trip is 2 cubic feet of heavy material, about 200 lb, a load most people can push. A pickup load is 0.75 ton, the payload of a full-size half-ton pickup (1,500 lb). A small single-axle dump truck carries about 6 tons.
Landscape rock calculator formula
A landscape rock calculator finds the tons of decorative stone you need to cover a bed. The formula is tons = length × width × (depth in inches ÷ 12) ÷ 27 × 1.4.
The division by 27 turns cubic feet into cubic yards. The 1.4 is the tons in one cubic yard of loose rock, which is an average. Tick the waste box and the calculator adds 10 percent, because rock settles into the soil and spreads thin at edges.
Worked examples
Example 1 is the default bed, 15 ft × 10 ft at 2 inches deep and $75 per ton.
- Volume: 15 × 10 × (2 ÷ 12) = 25 cubic feet
- 25 ÷ 27 = 0.926 cubic yards
- Tons: 0.926 × 1.4 = 1.30 tons
- Cost: 1.30 × $75 = $97.22
- With the 10 percent box ticked: 1.43 tons and $106.94
Example 2 is a side-yard strip, 30 ft × 12 ft at 3 inches deep and $90 per ton.
- Volume: 30 × 12 × (3 ÷ 12) = 90 cubic feet
- 90 ÷ 27 = 3.333 cubic yards
- Tons: 3.333 × 1.4 = 4.67 tons, $420.00
- With 10 percent extra: 5.13 tons, $462.00
At 5 tons, you are close to a delivery size where the truck, the drop location and the wheelbarrow trips matter. Ask the yard how much it will put on your driveway and where.
How far one ton goes
At 1.4 tons per cubic yard, one ton spreads across the following areas, before any extra.
| Depth | Area covered by 1 ton | Tons per 100 sq ft |
|---|---|---|
| 1 in | about 231 sq ft | 0.43 |
| 2 in | about 116 sq ft | 0.86 |
| 3 in | about 77 sq ft | 1.30 |
| 4 in | about 58 sq ft | 1.73 |
Cutting depth from 3 inches to 2 saves one third of the rock. Make sure the rock still hides the fabric. A good test is to spread a square foot by hand before you order.
Rock sizes and where they go
| Type or size | Typical use |
|---|---|
| 3/8 to 3/4 inch chips | Paths, small beds, tight borders |
| 1 to 2 inch stone | General beds, foundation borders |
| 2 to 4 inch cobble | Dry creek beds, drainage swales, accent areas |
| Larger boulders | Priced by piece, not by the ton in this calculator |
Smaller rock is easier to walk on and easier to rake. Larger rock is better on slopes and in swales because it does not wash away. Ask the yard whether the rock is washed, since dusty rock will cloud and may stain.
How to measure the bed
- Break the bed into rectangles and circles. Run each piece through the calculator and add the tons.
- For a curved bed, measure the longest length and the average of three widths.
- Measure depth with a stick after you have cleared sod. Check it in several spots.
- Allow for edging. If the rock will sit inside a steel or paver edge, the depth you enter should be the height from soil to the top of the edging.
- Subtract trees, stepping stones and downspout splash blocks that stay in the bed.
Common mistakes
- Using the depth you want after the rock settles. Stone presses into the ground, so the first pour looks thicker than the final layer.
- Skipping the barrier. Rock placed straight on soil mixes in over a season or two.
- Ordering the net amount. A delivery that is short by half a ton means a second trip charge.
- Leaving out the weight differences between rock types. Lava rock is much lighter than granite, and tons would be far fewer for the same volume.
- Placing the rock against siding. Keep it clear of the wall and follow your local rules on clearances near foundation and vents.
Related calculators
For a round, smooth stone bed, see the river rock calculator. A small walkway fits the pea gravel calculator, and the fabric under it can be sized with the landscape fabric calculator. To compare against mulch, use the mulch calculator.
Frequently asked questions
What counts as landscape rock?
Any decorative stone sold in bulk for beds, borders and ground cover, such as river rock, lava rock, crushed granite, marble chips and cobble. They are sized from about 3/8 inch up to several inches. The calculator uses one average weight of 1.4 tons per cubic yard for all of them.
Why is landscape rock priced higher than plain gravel?
Decorative rock is screened to a single size and color, often hauled farther, and sold in smaller lots. Plain base gravel is a bulk construction product. That is why the default price here is $75 per ton, and why you should ask your yard for its actual price and its weight per yard.
How deep should a landscape rock bed be?
A common range is 2 to 3 inches for small stone and 3 to 4 inches for larger stone. Too thin and soil or fabric shows through. Deeper than 4 inches costs more without improving looks, and it is harder to walk on and to rake.
Do I need fabric under landscape rock?
Most installers lay woven landscape fabric or a similar barrier first to keep rock from sinking into soil and to slow weeds. Weeds still seed into the top layer over time. Plan to pull them. The fabric itself is not in the calculator, so measure it separately.
How does landscape rock compare to mulch on cost over time?
Rock costs more at the start, but it does not rot, so you do not replace it every year or two as with mulch. It also holds heat, which some plants dislike, and it is harder to remove later. Compare your yard's price per ton to the mulch price per yard and your own plants.
Can I mix different sizes of landscape rock in one bed?
Yes. Large cobbles over a bed of smaller stone look natural and hold the stone in place. Calculate each size on its own area or depth and add the tons. If the rock sizes differ a lot in weight, ask your supplier for the weight per yard of each.
Estimates only. Verify quantities with your supplier before purchasing.