Gravel Calculator

Multiply the area you are covering, in square feet, by the depth in feet, then divide by 27 to get cubic yards - the unit gravel is delivered in. For a rectangle that is length x width x (depth in inches / 12) / 27. Enter your numbers above and the calculator also gives the volume in cubic feet, an approximate weight in tons, and a count of 0.5-cubic-foot bags.

Loose, dry gravel weighs about 1.4 to 1.6 tons per cubic yard. WSDOT lists 1.43 tons for crushed surfacing, 1.48 for crushed base course, and 1.55 for ballast, all measured dry as delivered. Pea gravel is lighter, roughly 1.25 to 1.4 tons. Compacted in place gravel is heavier - closer to 1.85 tons per cubic yard - and wet material adds another 10 to 15 percent, which is why the calculator shows a weight range unless you pick a type.

About 2 inches for a walkway or garden path, 2 to 3 inches for a patio or seating area, and about 4 inches over a compacted base for a shed pad or under pavers. A gravel driveway needs 3 to 4 inches of surface gravel over a 4 to 6 inch compacted base course. Place and compact deeper layers a few inches at a time.

A single-car driveway roughly 10 by 40 feet at 4 inches deep needs about 4.9 cubic yards, around 7 tons, of surface gravel, plus a compacted base of similar depth. A two-car driveway about 20 by 40 feet at 4 inches deep needs roughly 9.9 cubic yards, or 14 to 16 tons. Order the base course and surface gravel separately.

Yes. WSDOT recommends adding 10 percent to stockpiled quantities for handling waste. Gravel delivered loose also settles when compacted - often 20 to 30 percent for a driveway or base layer - so you place less volume than you buy. Use the optional waste / compaction field to raise the estimate; 10 to 15 percent suits most projects, more for a driveway base.

54 bags. A cubic yard is 27 cubic feet and each standard bag holds 0.5 cubic feet, so 27 / 0.5 = 54. Bagged gravel usually costs several times more per cubic foot than bulk, so bags are generally only worthwhile for jobs under about a cubic yard.

It does not change the volume. Cubic yards and cubic feet are pure geometry and depend only on the area and the depth. It does change the weight, because pea gravel, crushed stone, crusher run, and larger rock have different densities. That is why the calculator reports volume as one figure but weight as a range unless you select a specific type.

Bulk gravel, sold by the cubic yard or the ton and dropped by truck, is far cheaper per cubic foot. Bags only win when the job is small - under about a cubic yard, roughly 25 square feet at 4 inches deep - or when you cannot take a bulk delivery, since suppliers usually have a minimum order and a delivery fee.