A cubic yard is a volume, not a fixed weight
Choose the stone you plan to buy, then check its weight per cubic yard. The examples are particular suppliers’ products; another pea gravel or bagged gravel can weigh differently. Enter your supplier’s bulk weight when you have it. A solid rock’s density leaves out the gaps between stones and is the wrong figure here.
The result uses US short tons: 2,000 pounds per ton. The bags use the volume you enter, independently of the weight estimate. If a bag only lists pounds, get its stated volume before using the bag count.
Keep depth and compaction separate
Measure the layer you want to fill. Extra starts at zero and is shown in the order, so you can add a supplier’s allowance without hiding it in the depth. The calculator does not guess how much your stone compacts.
For a compacted base, give the supplier the finished layer volume and ask for the loose amount needed to make it. If you are laying paving on top, the paver calculator keeps pavers, base and bedding sand separate, and the gravel driveway calculator works out each layer of a driveway.
How much extra to order
For a compacted path or base, Maine’s gravel road manual shows multiplying the compacted volume by about 1.11, which is 11 percent extra. Ask your supplier for its own figure for the stone you buy. For a loose decorative layer, none of the public bodies we cite gives a figure, so the field starts at zero.
Decorative stone and river rock
Decorative rock is ordered the same way: area times depth, then weight from the supplier’s figure. The examples include a 3 to 7 inch river rock and a 2 to 3 inch cobble at 2,500 and 2,600 lb per cubic yard. Larger stones need a deeper layer to cover the ground; the FHWA’s rule for gravel roads is a layer at least twice as thick as the largest stone.
Leave a usable path around the beds
Mark the path on the ground before measuring stone. The raised-bed path guide helps you check the room left for walking and carrying bags.