How to estimate gravel for a driveway or path
Area x depth gives volume; convert to cubic yards and account for compaction.
Gravel is typically ordered by volume (cubic yards). Your inputs are usually area and target depth, so the estimate is a volume conversion problem. The trick is choosing the right depth for the job and the right material for the layer.
The two common mistakes are forgetting compaction and mixing up layers. Many projects use a compactable base (crushed stone/road base) plus a separate top layer (pea gravel or decorative rock). Those layers can have different depth targets and behave differently.
Step-by-step: gravel math
- Measure the area to cover (length x width), or break irregular shapes into rectangles and add them. Measure the finished footprint, not the size of the gravel pile you plan to dump.
- Choose a compacted depth target for each layer (base vs top). Depth depends on use (walkway vs driveway) and soil conditions (project dependent).
- Convert area x depth to volume (cubic feet or cubic meters). If depth is in inches, convert to feet first (in / 12).
- Convert volume to cubic yards for ordering (1 yd3 = 27 ft3). If your supplier sells by tons, use their yards-to-tons conversion for the exact product and moisture condition.
- Add a buffer for compaction, uneven grade, and edge loss. Many driveways and bases are compacted in lifts; placing a thick loose layer and hoping it compacts evenly is a common cause of settlement later.
Practical tips
- Base layers and top layers can have different depths and different materials—estimate them separately so you don't accidentally order the wrong product at the wrong thickness.
- Compaction reduces installed height; ordering slightly extra prevents shortages. If you're unsure, order the base first, compact and grade, then re-measure before ordering the top layer.
- Edging and containment keep gravel from spreading and reduce long-term maintenance. Without edging, some gravel will migrate into grass and walkways over time.
- Confirm the material type and supplier conversion if you're ordering by tons. Density varies by product and moisture; supplier tables are usually more reliable than generic averages.
Quick checklist
A good gravel order comes from measuring the finished footprint, choosing the right depth per layer, and adding a realistic buffer for compaction and grade.
- Measure the finished area (length x width) or break the shape into rectangles and add them. Estimate base and top layers separately if you're using different materials.
- Use compacted (installed) depth for your target. Convert inches to feet before multiplying (in / 12), then convert cubic feet to cubic yards (divide by 27).
- If ordering by tons, use your supplier's yards-to-tons conversion for the exact product and typical moisture. Density varies enough that generic averages can be off.
- Add buffer for compaction, uneven grade, and edge loss, then round up to delivery quantities. It's usually cheaper to have a little extra than to pay a second delivery fee.
Gravel estimate notes
Gravel is often purchased by weight (tons) but planned by volume (cubic yards). Density varies with material type, moisture, and compaction, so conversions differ between suppliers.
Depth is the biggest swing factor—small depth changes across a large driveway or path can change tonnage a lot.
If you’re building a driveway, you may need multiple layers (base + top). Treat them as separate materials and depth targets.
- Ask your supplier for their yards↔tons conversion for the specific gravel.
- Plan extra for compaction and edge irregularities.
- Consider base layers separately if you’re building up a driveway.
- If drainage is an issue, correct grading before adding material—otherwise you may chase low spots forever.
Gravel layers & compaction notes
Depth is the biggest swing factor. Decide whether your depth is loose depth or compacted depth, and estimate base vs top layers separately.
- Take multiple depth checks and use an average thickness.
- Ask your supplier for the exact yd³↔tons conversion for the product you’re buying.
- Plan a buffer for compaction and edge irregularities to avoid a second delivery.
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