Stone calculator for Hawaii

Crushed stone is typically purchased by the ton. For most grades, use about 2,800 lb per cubic yard, which works out to 1.4 tons per yard. This stone tonnage calculator uses the selected material's precise weight across twelve graded products, covering 3/8 inch chips through 2.5 inch railroad ballast. Contractors often begin with a specification number, while homeowners start with the project itself. The guide below helps match either approach to the stone needed.

How to calculate

1. For pads and drives, get the footprint in feet by multiplying length and width. For drains, use trench length multiplied by trench width.
2. Choose the depth based on the layer's function. Finish layers are 2 to 3 inches, base layers are 4 inches, and French drains require 12 inches or more.
3. Divide cubic feet by 27 to find cubic yards. Multiply yards by 1.4 for tons of typical crushed stone.

Weight by stone type

Understanding size labels

Stone grade numbers refer to rock size, with lower numbers used for larger pieces. #4 contains rock from 1-2 inches. For drainage, driveways, and concrete applications, #57 at 3/4 to 1 inch is a common choice. #67 ranges from 1/4 to 3/4 inch and is often used as pipe bedding. #8 measures about 3/8 to 1/2 inch, while #89 includes material from 3/8 inch down to fines for paver joints and finishing courses. Screenings combine fine dust and chips into a compactable, screed-ready layer. Railroad ballast uses angular rock measuring 1 to 2.5 inches to support tracks and equipment pads while letting water pass through.

Clean stone or fines: choose the right type

There are two main stone categories here. Washed, clean material such as #57 remains open and lets water through, making it suited to drainage. Materials containing fines, including crusher run and road base, compact into a firm layer for bases. Using the wrong one causes problems: crusher run in a French drain can retain water, while a #57 driveway base can continue to move. When plans or permits specify a gradation, use that exact specification. If terminology is unclear, send the line item through our contact form; "3/4 clean" and "#57" can refer to the same material under different names.

Common stone quantities

Example calculation: a 30-foot French drain

A 30 feet long trench that is 12 inches wide and 12 inches deep contains 30 cubic feet. This equals 1.1 cubic yards, or 1.6 tons of #57. Although a 4-inch pipe in the center takes up about 0.1 yards, order the full 1.6 tons and place the small extra amount at the outfall. Line the trench with non-woven fabric before placing stone so heavy red clay on windward lots does not fill the drainage voids.

Two ways to avoid ordering errors

• Check the specification first, then verify the local term. Crusher run and crush and run name the same material, and #57 is the same stone as "57s".
• Allow for 5 to 10% compaction when angular stone will be rolled. The calculator's extra-percent option addresses ordinary settling, but engineered base work follows its specified compacted depth.
• For pavers, use compacted base stone for support, then screenings or concrete sand as the thin leveling layer. On soft ground, dust alone should not be used beneath pavers.
• Calculate the trench volume before accounting for the pipe. A pipe below 6 inches usually takes up less than a wheelbarrow load, so it seldom changes the amount ordered.

Crushed-stone reference figures

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