Cubic yards is the unit that confuses every homeowner walking into a landscape supply yard. A cubic yard is a volume: 3 feet long, 3 feet wide, 3 feet tall. That is 27 cubic feet. It sounds abstract until you realize that one cubic yard of mulch fills a wheelbarrow about 9 times, and one cubic yard of gravel weighs over a ton.
This calculator converts your project dimensions directly to cubic yards, the unit landscape suppliers use for pricing and delivery. It also shows the equivalent in standard retail bags (2 cubic feet each) so you can compare the cost of buying bags at the hardware store versus ordering bulk delivery from a landscape yard.
The cost breakpoint between bags and bulk is the key decision. A 2-cubic-foot bag of mulch costs $3 to $5 at a hardware store. A cubic yard of bulk mulch (equivalent to 13.5 bags) costs $25 to $45 delivered. At 3 cubic yards (about 40 bags), bulk delivery saves $30 to $60 and eliminates the labor of loading, transporting, cutting open, and emptying 40 individual bags.
For gravel and stone, the breakpoint is even lower because bags are heavier and more expensive. A 50-pound bag of pea gravel (about 0.5 cubic feet) costs $4 to $6. A cubic yard of bulk pea gravel (equivalent to 54 small bags) costs $35 to $55 delivered. At just 1 cubic yard, bulk saves $150 or more.
One cubic yard of mulch equals 13.5 bags at 2 cubic feet each and covers approximately 108 square feet at 3 inches deep.
The formula is straightforward: length (feet) times width (feet) times depth (feet) divided by 27 equals cubic yards. Since depth is typically measured in inches, convert first by dividing by 12. Example: 30 feet long, 10 feet wide, 3 inches deep = 30 x 10 x 0.25 = 75 cubic feet, divided by 27 = 2.78 cubic yards.
Bag count conversion: divide total cubic feet by the bag volume. Standard mulch bags are 2 cubic feet. Standard gravel bags are 0.5 cubic feet. So 75 cubic feet of mulch = 37.5 bags (round up to 38). The same volume in gravel bags = 150 bags, which illustrates why gravel almost always justifies bulk delivery.
Weight estimates help you plan logistics. Mulch: 400 to 600 pounds per cubic yard. Topsoil: 2,000 to 2,400 pounds per cubic yard. Gravel: 2,600 to 3,000 pounds per cubic yard. River rock: 2,400 to 2,800 pounds per cubic yard. A typical pickup truck bed holds about 1 to 1.5 cubic yards of mulch but should not carry more than 0.5 cubic yards of gravel due to weight limits.
Use this calculator whenever you need to convert a measured area and depth into a purchase quantity. It applies to mulch, gravel, topsoil, sand, compost, and any other bulk landscape material sold by the cubic yard. It is especially useful when comparing prices between retail bags and bulk delivery, or when estimating how many pickup truck loads you need for a self-haul project.