Ordering too little gravel means a second delivery charge; ordering too much means a pile you'll spend weeks moving. This guide covers how to measure your project area, convert volume to tons, choose the right aggregate for your application, and account for compaction so your first order is your only order.
Measuring Your Area and Converting to Cubic Yards
Start by measuring the length and width of your project in feet. For rectangular areas, multiply length × width to get square footage. For circular areas, use π × (radius)² — the calculator handles this automatically when you select the circle shape. For irregular areas, break the shape into rectangles, calculate each section separately, and add the totals together.
Once you have square footage, multiply by the depth in feet to get cubic feet. Because gravel depth is usually specified in inches, divide the inch measurement by 12 first: 4 inches becomes 0.333 feet. Then divide cubic feet by 27 to convert to cubic yards, the standard unit for ordering bulk aggregate. Most suppliers sell by the ton, not by the yard, so you will also need to multiply cubic yards by the material's bulk density to get tons. For example, standard #57 crushed stone weighs about 1.4 tons per cubic yard; pea gravel is lighter at about 1.3 tons per cubic yard.
Compaction Allowance: Why You Need to Order Extra
Gravel delivered loose from a truck will settle 10–20% after it is spread and trafficked. If you order exactly the volume you calculated, your finished surface will be shallower than designed. For structural applications like driveways, add a 15% compaction allowance; for decorative paths and garden beds with no vehicle traffic, 5% is usually sufficient.
The compaction rate depends on the material: angular crushed stone locks together tightly and compacts less than round pea gravel, which rolls and shifts more under load. If you are building a base course and a surface course, calculate each layer separately using its own density and compaction rate. Also account for the existing grade — if you need to cut down a high spot or fill a low spot before placing gravel, your net volume will differ from the surface area calculation. Measure to the finished grade you want, subtract any cut, and add any fill to get the true material requirement.
Choosing the Right Aggregate for Your Project
Aggregate selection depends on the application. For driveway base courses, #57 crushed stone (1 inch down to 1/4 inch) or #67 crushed stone (3/4 inch down to 1/4 inch) are the standard choices. Both compact well under traffic, drain freely, and are load-bearing. A 4-inch compacted base of #57 is the minimum for a residential driveway; 6 inches is preferred for heavy vehicles or poor subgrade conditions.
For decorative paths and garden beds, pea gravel (3/8 inch round) is popular because of its smooth appearance, but it rolls underfoot and migrates over time. Decomposed granite (DG) compacts into a firm surface and is a better choice for high-traffic paths. For drainage applications (French drains, retaining wall backfill, foundation drainage), use clean washed stone with no fines — #57, pea gravel, or river rock. Avoid crushed fines or limestone screenings in drainage applications because the fine particles fill air voids and reduce drainage capacity.
Understanding Truck Loads and Delivery Minimums
Most gravel suppliers deliver by truck rather than bag. A single-axle dump truck typically carries 10–12 tons; a tandem-axle truck carries 18–22 tons. Knowing how many truck loads you need lets you plan delivery access and schedule drops at the right location on your property, since moving gravel even 50 feet by wheelbarrow is slow, exhausting work that adds hours to any project.
Suppliers usually have a minimum order — commonly 5–10 tons — and charge a flat delivery fee plus a short-load fee if you order below the minimum. If your project needs only 2–3 tons, check whether a local supplier sells by the bag (typically 50-lb or 0.5 cubic foot bags) or allows you to pick up a small amount in your own truck. For large projects over 20–30 tons, ask about bulk pricing discounts and confirm that delivery trucks can access your site without damaging underground utilities, irrigation lines, or a soft lawn.
Depth Guidelines by Application
Using the right depth for each application prevents both under-performance and wasted material. For decorative gravel paths and garden beds, 2–3 inches of gravel provides adequate weed suppression and visual coverage without excessive cost. Always install landscape fabric beneath decorative gravel to prevent soil from mixing upward into the stone layer over time.
For residential driveways, the standard recommendation is 4–6 inches of compacted base course, plus an optional 1–2 inch surface layer of finer material for improved appearance and comfort underfoot. For patios without a concrete or paver surface, 4 inches of compacted crushed stone creates a stable and level surface. For French drain trenches and foundation drainage, fill the trench to the pipe level with clean washed stone and cap with 3–4 inches of stone above the pipe before backfilling with soil. These depth recommendations assume average soil conditions — clay soils or heavy traffic may require additional base depth or a geotextile fabric separator between the native soil and the aggregate layer.