How to Work Out How Much Material You Need

The formula, and how to actually use it

Bulk material is sold and delivered by the cubic yard, and cubic yards come from one formula: length in feet times width in feet times depth in feet, divided by 27. That division by 27 converts cubic feet into cubic yards, since a cubic yard is 3 feet by 3 feet by 3 feet. Say you are covering a bed 20 feet long and 8 feet wide at 3 inches deep. Convert 3 inches to feet first, that is 0.25 feet. 20 times 8 times 0.25 comes to 40 cubic feet. Divide by 27 and you need about 1.5 cubic yards. A second example: a 12 by 12 patio base at 4 inches of aggregate depth. 4 inches is 0.33 feet. 12 times 12 times 0.33 is about 47.5 cubic feet, divide by 27 and that is roughly 1.75 cubic yards.

Depth changes the answer more than people expect

Doubling the depth doubles the volume needed for the same footprint, because depth is one of three multiplied terms in the formula, not an afterthought tacked on at the end. Two inches of mulch over 500 square feet takes about 3.1 cubic yards. Three inches over the same 500 square feet takes about 4.6 cubic yards, close to half again as much material for one more inch. Before ordering, decide the actual working depth the job calls for and measure to it, rather than guessing at a round number and hoping it is close.

Why a bigger stone covers less ground per ton

Aggregates and decorative stone are often sold and delivered by weight rather than volume, and weight-to-coverage is not the same across every size. Larger stone has more air gaps between pieces than smaller stone does, and a ton of large boulders or bigger flagstone pieces simply takes up more physical space with fewer solid pieces per ton than the same weight of crushed gravel or sand does. That means a ton of a coarse aggregate like No. 57 stone covers noticeably less ground at a given depth than a ton of fine material like M-10 sand. When you are estimating a job with a larger decorative stone, do not assume the same tons-per-area ratio that worked on a fine aggregate job last time. Ask at the counter what a given product's typical coverage looks like at the depth you are planning.

Bulk yard, bag, or one-ton bulk bag

Straight bulk by the cubic yard is the cheapest way to buy material and the right call for anything past a small job, a full patio base, a large bed, a driveway resurface. Bagged material costs more per unit of coverage but makes sense for small top-ups, a single planter, patching a thin spot in an existing bed, or any job where a truck cannot get close enough to dump loose material. The one-ton bulk bag sits in between: $17 for the bag itself, loaded with material, useful when you need bulk-scale volume delivered somewhere a dump truck cannot access, or when you want a contained, liftable load for a forklift delivery rather than a pile dumped on the driveway.

Getting it delivered

Dump delivery runs on a tandem truck that carries 1 to 18 tons or yards in a single load, priced by distance from the yard: $75 for 0 to 10 miles, $125 for 10 to 20 miles, $175 for 20 to 30 miles. That is a loose pile dumped where the truck can reach. Forklift delivery handles palletized and bagged material and is priced on request, the right option for pavers, wall block, or bagged goods that need to land in a specific spot rather than a dumped pile. Picking up from the yard yourself is always an option too, Monday through Friday 7:30am to 5pm, Saturday 8am to 2pm, closed Sunday.

What to bring to the counter

• Your measured length, width, and planned depth for each area, not a rounded guess.
• Whether the material is sold by the cubic yard or by the ton, since the two don't convert the same way for every product.
• Whether the load needs to be dumped or set with a forklift, and how far the delivery address is from Marietta.
• Any existing depth already in place if you are topping up rather than starting from bare ground, since that changes how much new material you actually need.

Working the math out before you arrive, or even just bringing accurate measurements, means the amount that gets loaded onto the truck is the amount the job actually needs, not a guess that runs short halfway through or leaves a half pallet sitting in the driveway afterward.