Gravel Calculator
Size a gravel order in tons for a driveway layer or a french drain trench, from typical per-yard densities for crushed stone and pea gravel. Everything runs in your browser.
How to use
- Pick what you are filling: a layer over an area, or a french drain trench.
- For a layer, enter the area in square feet and the gravel depth in inches. For a trench, enter length in feet and width and depth in inches.
- Choose the material. The calculator carries typical supplier densities: crushed stone at about 1.35 tons per cubic yard, pea gravel at about 1.4.
- Read the tons, then round up. Suppliers deliver in half-ton or full-ton steps, and gravel left over is cheaper than a second delivery fee.
How the math works
Volume comes first: area times depth for a layer, or trench length times width times depth for a drain, with inches divided by 12 to land in cubic feet. Cubic yards divide by 27, and tons multiply the yards by the material's density, 1.35 for crushed stone and 1.4 for pea gravel per loose cubic yard. Those densities are typical supplier values, not a standard. Results are rounded to two decimals.
Tonnage is computed on loose gravel as delivered. Gravel compacts after spreading, so the finished layer settles below the loose height; base preparation and compaction change the real-world result.
Order round and above. Deliveries come in half-ton steps, a short load costs a second trip, and about 10 percent extra gravel disappears into ruts, spillage, and soft ground.
Frequently asked questions
Is anything I enter uploaded or stored?
No. The calculator runs entirely in your browser tab, and your numbers never leave the page. Nothing is stored, nothing is sent to a server, and the page sets no cookies. Ad slots on the page are served by third-party networks, which follow their own privacy policies.
Where do the tons-per-yard numbers come from?
From typical supplier spec sheets, not a national standard: crushed stone weighs about 1.35 tons per loose cubic yard and pea gravel about 1.4, because round pea gravel packs slightly denser. Real weights vary by quarry and moisture, so treat the tonnage as an order guide and let your supplier confirm.
How does the french drain mode work?
A trench is just a long narrow box, so the volume is length times width times depth, converted to cubic yards and weighed like any other pile. The drain pipe's own volume is not subtracted; the gravel around it more than covers the difference, and erring high is the safe side for a drainage job.
How deep should a gravel driveway or french drain be?
A light-use driveway layer usually sits 4 to 6 inches deep over compacted base, and walkways less. A french drain trench commonly runs 12 to 24 inches deep and 6 to 12 inches wide, with the pipe set on gravel and covered past the top of the pipe. These are typical figures, not a spec for your soil; when water is the problem, a local excavator's opinion is worth the call.