Gravel Coverage Calculator

Notes for construction takeoffs

Gravel coverage is driven by three jobsite realities: uneven subgrade, compaction after placement, and density changes from moisture and gradation. Adding a waste factor helps avoid short loads.

If your supplier sells by cubic yard, use the alternate volume figure. If they sell by weight, use the tons result.

Gravel coverage planning for site work

Reliable gravel quantities prevent stalled crews and extra trips. This calculator turns measured area, target depth, and material density into ordering numbers that match how suppliers quote bulk aggregate.

Depth ranges used in the field

Decorative rock beds often finish at 2–3 inches. Walkways and light paths commonly use 3–4 inches for stable coverage. Drive lanes and equipment pads frequently need 4–6 inches, and parking stalls may require more depending on traffic. Base layers under pavers may reach 4–8 inches with weaker subgrades.

Common density values to start with

Bulk density depends on gradation and moisture. Typical delivered values are about 1,600 kg/m3 for crushed stone, 1,700 kg/m3 for pea gravel, and 1,500 kg/m3 for rounded river rock. In imperial terms, many aggregates fall near 95–110 lb/ft3. When available, use your supplier’s density for conversions.

Why compaction changes coverage

Loose material settles when spread and plate-compacted. Adding 0–10% compaction allowance helps you reach the finished thickness after vibration and traffic. Thin decorative lifts usually need less; thicker lifts on soft subgrade may need more. If you compact in two lifts, allow for settlement in each lift.

Waste factor for realistic ordering

Waste covers spillage, trimming, edge blending, and small over-excavations. Many crews use 5–12% depending on access and layout. Simple rectangles on firm grade can use the low end; irregular beds and hand placement benefit from higher waste. If material must be wheelbarrowed, waste can rise due to handling losses.

Selecting the right shape input

Rectangles fit driveways, slabs, and storage yards. Circles work for fire-pit pads and tree rings. Triangles handle wedges and tapers along fences or curbs. If you already have a takeoff area from drawings, use custom area to match your estimator’s quantity sheet.

Interpreting volume and weight outputs

Use adjusted volume when purchasing by cubic yard or cubic meter. Use adjusted tons when purchasing by weight. As a reference, 1 cubic yard equals 27 cubic feet. If the two do not match a ticket conversion, the density assumption is different—update density and recalculate before ordering. Keep moisture in mind when comparing tickets.

Quick site checks after delivery

Measure depth at multiple points, especially edges and transitions. Wet material can weigh more and cover less, while dry material can be fluffy and settle later. Spread in controlled lifts, compact, then recheck thickness. Accurate inputs produce dependable orders and cleaner, longer-lasting finishes.

FAQs

1) How do I choose the correct depth?

Use 2–3 inches for decorative beds, 3–4 inches for paths, and 4–6 inches for light drive areas. For bases under pavers, 4–8 inches is common. Match depth to loads and subgrade quality.

2) Why does gravel density matter so much?

Vendors convert between volume and weight using density. Moisture and gradation change density, so the same cubic yard can weigh differently. Entering a supplier density makes tons and yards align with delivery tickets.

3) What waste factor should I enter?

Start with 7% for typical projects. Use 5% for simple rectangles with good grade control. Use 10–12% for curved edges, tight access, or hand spreading where spillage and trimming increase.

4) What is compaction allowance?

It adds extra material so the finished layer still meets your target thickness after raking, vibration, and traffic. If you compact aggressively or place thicker lifts, a small allowance helps prevent thin spots.

5) My supplier sells by cubic yard—what should I use?

Use the adjusted volume output and the alternate yd3 figure shown for imperial inputs. If the supplier uses a different density for conversions, enter that density so your estimate matches their invoice units.

6) Can I estimate bagged gravel too?

Yes. Enable bag estimate, enter bag weight, and the calculator rounds up to whole bags. Add a per-bag price if you want a cost estimate for small repairs or tight-access sites.

7) How can I verify coverage on site?

After spreading, check depth at several points with a ruler or stake marks. Compare delivered quantity to the adjusted estimate. Differences usually come from moisture, uneven subgrade, and thickness changes at edges.