Stone calculator for Illinois

Most crushed-stone grades are sold by the ton and convert at roughly 2,800 lb for each cubic yard, or 1.4 tons per yard. Use this calculator for graded materials from 3/8 inch chips up to 2.5 inch railroad ballast, with the selected product's weight applied to the result. A contractor may start with a specification, while a homeowner may begin with the project itself. The reference below connects both descriptions to the appropriate stone.

Calculation steps

1. For pads and driveways, find square footage by multiplying length and width in feet. For drains, multiply the trench length by its width.
2. Set the depth according to the layer: use 2 to 3 inches for a surface course, 4 inches for base, and 12 inches or more for French drains.
3. Convert cubic feet to cubic yards by dividing by 27. Then multiply yards by 1.4 for typical crushed-stone tons.

Product stone weights

Understanding stone sizes

Stone grades identify size ranges, with lower numbers indicating larger pieces. At 3/4 to 1-1/2 inches, #4 is coarse. #57 measures 3/16 to 1 inch and is used for drainage, driveways and concrete work. The finer #67 grade is 1/4 to 3/4 inch, often used around pipe. #8 is about 3/32 to 3/8 inch, while #89 goes from 3/8 inch to fines, making both useful in paver joints and finish layers. Screenings combine dust with small chips and compact into a firm bed for screeding. Railroad ballast is heavy, angular rock measuring 1 to 2.5 inches; it drains while supporting tracks and equipment pads.

Choosing clean stone or fines

Stone choices here fall into 2 groups. Washed, clean material such as #57 leaves open spaces for water to move through, which suits drainage in slow-draining prairie clay. Crusher run, road base, and other mixes containing fines compact into a firm layer for bases. Using the wrong group causes problems: fines can block a French drain, while a #57 base can keep moving under a driveway. When a drawing or permit lists a gradation, order the material it specifies. If the product name is confusing, text the line item to (847) 469-1546; "3/4 clean" and "#57" may be different names for the same stone.

Common stone quantities

Example: a 30-foot French drain

Start with the trench volume: 30 feet in length, 12 inches across and 12 inches deep equals 30 cubic feet. That works out to 1.1 cubic yards, or 1.6 tons of #57. Although a 4-inch pipe occupies about 0.1 yards, order the complete 1.6 tons and place the slight excess at the outfall. Put non-woven fabric around the trench before adding stone so prairie clay does not fill the drainage voids.

Two ways to avoid ordering errors

• Use the specified material first, then verify its local name. Crusher run and crush and run describe the same product, just as #57 and "57s" describe the same stone.
• Plan for 5 to 10% compaction when angular stone will be rolled. Use the calculator's extra-percent toggle for ordinary settling, while engineered base work should follow its specified compacted depth.
• A paver installation relies on compacted base stone for support, with screenings or concrete sand used as the thin leveling layer. Do not use dust alone beneath pavers where ground is soft.
• Base the calculation on the trench volume rather than the pipe. A pipe smaller than 6 inches usually removes no more material than a wheelbarrow load.

Crushed stone facts

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