Gravel Calculator
Volume = length × width × depth, converted to yards; tons use the density above.
A gravel calculator converts the area you need to cover and the depth you want into cubic yards, tons, and an estimated cost, so you order the right amount of material on the first trip to the supplier. This page explains the formula behind the gravel calculator, walks through a worked example for a driveway, and lists the mistakes that lead to running short or badly overordering.
What the Gravel Calculator Finds
Gravel is sold and delivered by weight, typically the ton, but most people plan a project in square feet of area and inches of depth, which is where a gravel calculator bridges the gap. Enter the length and width of the area you are covering along with your target depth, and the gravel calculator returns cubic feet, cubic yards, and an estimated tonnage based on a standard crushed-stone density. Because gravel is heavy and delivery is often priced by the load, getting this number right the first time avoids paying for a second delivery just to finish a driveway or path.
How to Use the Gravel Calculator
Measure the length and width of the area in feet, and decide on a depth in inches based on the project: driveways typically need 4 to 6 inches, while a decorative garden path might only need 2 inches. Enter all three numbers into the gravel calculator, and it will return volume in cubic yards along with the estimated weight in tons using a default density of about 1.4 tons per cubic yard. If your supplier quotes a different density for the specific gravel type you are buying, adjust the density field in the gravel calculator so the tonnage estimate matches what you will actually be billed for.
Gravel Formula and Worked Example
The formula is volume = length × width × depth, with depth converted from inches to feet by dividing by 12, then the result divided by 27 to convert cubic feet to cubic yards. For a driveway 40 feet long and 12 feet wide at a 5-inch depth: volume = 40 × 12 × (5 ÷ 12) = 200 cubic feet, then 200 ÷ 27 ≈ 7.4 cubic yards. At 1.4 tons per cubic yard, that is 7.4 × 1.4 ≈ 10.4 tons of gravel. The gravel calculator performs this exact chain of conversions automatically and also applies a rounding buffer so the final number matches how suppliers sell material, usually in half-ton or full-ton increments.
Common Gravel Coverage by Depth
| Depth | Coverage per Ton | Best Use |
|---|---|---|
| 2" | ~150 sq ft | Decorative paths, mulch borders |
| 4" | ~75 sq ft | Garden paths, light foot traffic |
| 6" | ~50 sq ft | Driveways, vehicle traffic |
| 8" | ~38 sq ft | Heavy-duty base layers |
A gravel calculator applies these same coverage ratios automatically, so this table is mainly useful as a fast sanity check on a delivery quote.
Gravel Types and Density
Crushed stone, the most common driveway base material, weighs about 1.4 tons per cubic yard when compacted, and that is the default density most gravel calculator tools assume. Pea gravel is rounder and packs slightly less densely, closer to 1.3 tons per cubic yard, while larger decorative river rock can weigh more per cubic yard depending on the stone size. Always check with your specific supplier if you are ordering anything other than standard crushed stone, since a gravel calculator's tonnage estimate is only as accurate as the density value entered.
Mistakes to Avoid
The single biggest mistake is forgetting to account for compaction: loose gravel settles by roughly 10 to 20 percent once it is spread and driven over, so ordering the exact number a gravel calculator returns without any buffer often leaves a driveway short by the following season. Skipping a proper sub-base or landscape fabric under the gravel layer lets it sink into soft soil over time, effectively wasting a portion of every ton delivered. Measuring an irregular area as a single rectangle instead of breaking it into smaller rectangular sections produces a gravel calculator estimate that is noticeably off for L-shaped or curved driveways. Finally, ignoring drainage slope during installation can cause water to pool on the gravel surface instead of running off, regardless of how accurately the material quantity was calculated.
Cost Estimating Tips
Gravel is typically priced per ton delivered, with the price varying by region, gravel type, and how far the delivery truck has to travel from the quarry. A gravel calculator that includes a cost field lets you compare quotes from different suppliers using the same tonnage figure instead of comparing rough estimates. Delivery minimums are common, so a small path project might cost more per ton than a large driveway simply because the load does not meet a supplier's full-truck discount threshold. Always ask whether a quoted price includes delivery and spreading, since spreading gravel by hand over a large area adds meaningful labor time to a weekend project.
Related Calculators
Gravel is often just one material in a larger landscaping or construction project. If you are also placing topsoil or mulch nearby, check the topsoil calculator and mulch calculator for matching coverage estimates, and use the concrete yard calculator if the project includes a poured slab or footing next to the gravel area. Running each material through its own calculator, starting with the gravel calculator for base layers, keeps a multi-material project's ordering accurate from the ground up.
FAQ
How does a gravel calculator convert area into tons?
A gravel calculator multiplies length, width, and depth to get cubic feet, converts to cubic yards by dividing by 27, then multiplies by roughly 1.4 tons per cubic yard, which is the typical density of compacted crushed gravel.
How deep should a gravel driveway be?
Most gravel driveways use 4 to 6 inches of base material, sometimes with a separate 2-inch top layer of finer decorative gravel. A gravel calculator should be run separately for the base layer and the top layer if you are using two different materials.
Does gravel weight change by type?
Yes. Crushed stone runs about 1.4 tons per cubic yard, pea gravel is close to 1.3, and larger river rock can run slightly heavier. A gravel calculator with an adjustable density input gives a more accurate order for anything other than standard crushed stone.
How much extra gravel should I order?
Add 10 percent to whatever a gravel calculator returns to cover an uneven sub-base, settling, and spillage during spreading, especially on a larger driveway or drainage project.