How much gravel do you need?

How do I calculate how much gravel I need?

Multiply the area by the depth to get the volume, convert it to cubic yards, then multiply by the stone's weight per cubic yard if your supplier sells by the ton. A 20 ft by 10 ft area at 3 inches deep holds 50 cubic feet, or about 1.85 cubic yards. In pea gravel at about 1.35 tons per yard, that is roughly 2.5 tons before any extra for settling.

How many tons of gravel are in a cubic yard?

Loose, most gravel weighs about 1.3 to 1.5 tons (2,600 to 3,000 lb) per cubic yard. The Minnesota DOT counts one-size stone such as #57 or pea gravel at 1.35 tons a yard and road base in the truck at 1.4; Washington State DOT weighs crushed surfacing at 1.43 to 1.48 tons a truck-measured yard and Caltrans uses 1.5. Rounded stone such as river rock sits at the lighter end because of the gaps between stones; crusher run and road base sit at the heavier end because their fines fill those gaps. Moisture and the quarry's rock change the number too, so if your supplier quotes a weight, enter it in the Weight field.

How deep should gravel be?

For decorative cover and garden beds, 2 to 3 inches is usually enough. Walkways typically get 2 to 3 inches of top stone, over a compacted base where the ground is soft. A new driveway is built in layers: coarse crushed stone at the bottom, crusher run or road base in the middle and about 2 inches of surface gravel on top, commonly 6 to 12 inches in total depending on the soil and the traffic. Topping up an existing driveway usually takes 2 to 3 inches. Figure each layer separately, since each one is a different stone.

How many bags of gravel are in a cubic yard?

A standard 0.5 cubic foot bag, about 50 lb, is 1/54 of a cubic yard, so one yard takes 54 bags. Bags make sense for small jobs like filling a planter or patching a path. Past roughly half a cubic yard, bulk delivery is often cheaper even after the delivery fee. Enter your local prices above to see where the line falls for you.

Why order extra gravel?

Stone settles as it is spread, and a compacted base shrinks noticeably when it is tamped: a 4-inch compacted layer of crusher run starts out as roughly 4½ to 5 inches of loose stone. Plan on 5 to 10% extra for loose decorative stone and 15 to 25% for a compacted base. Bulk stone is usually sold in half or whole tons or yards, so round up to the next step.

Sources: Minnesota DOT, Grading and Base Manual, 5-692.430 (soil and aggregate conversion factors); WSDOT Design Manual M 22-01, Exhibit 620-1; Caltrans Maintenance Manual, Vol. 1, Appendix (weights of materials); U.S. EPA, Standard Volume-to-Weight Conversion Factors. How we check our calculators.