Step 1: Measure Your Area
For rectangular areas, measure the length and width in feet with a tape measure. For irregular shapes, break the space into rectangles and measure each separately — a curved path, for example, becomes three or four straight segments. For circles, measure the radius (center to edge), square it, and multiply by 3.14 for square footage. Round measurements up, not down; running short mid-project means a second delivery fee that usually costs more than the extra stone would have.
Step 2: Choose the Right Depth
Depth is where most estimates go wrong, and it depends entirely on what the gravel needs to do. Decorative ground cover only needs 2 inches over landscape fabric. Surfaces that carry foot traffic need 2–3 inches. Anything supporting vehicles needs 4–6 inches built in compacted layers — see the driveway calculator for the standard base-plus-surface structure. Drainage applications like French drains need 12 inches around the pipe. When in doubt between two depths, price both with the calculator; the difference is often smaller than expected because gravel is cheap relative to delivery.
Step 3: Convert Volume to Weight
Suppliers quote bulk gravel per ton, so you'll need the conversion: divide your cubic feet by 27 to get cubic yards, then multiply by the material's density. Most gravel runs 1.4–1.6 tons per cubic yard — pea gravel at the light end (1.4), crushed stone in the middle (1.5), and compacting base materials at the heavy end (1.6). The full density and coverage tables are on the coverage chart.
Step 4: Bags or Bulk?
The break-even is about one cubic yard. Below that, bagged gravel from a home improvement store is convenient and avoids delivery fees — you'll need roughly 54 half-cubic-foot bags per cubic yard. Above one yard, bulk wins decisively: a cubic yard in bags costs $216–324 at typical bag prices, versus $40–80 for the same volume in bulk plus a delivery fee that's spread across the whole order. For projects over 3–4 yards, bulk delivery is the only sensible option.
The Two Mistakes That Ruin Gravel Orders
First, forgetting compaction. Gravel settles and compacts 5–10% after spreading, more for crusher run under mechanical compaction. An exact-quantity order reliably comes up short, which is why every calculator on this site recommends the 5–10% buffer. Second, mixing up cubic yards and tons when comparing supplier quotes. One quotes $45/yard, another $32/ton — the per-ton quote sounds cheaper but a yard of crushed stone is 1.5 tons ($48), making the per-yard quote the better deal. Always convert both quotes to the same unit before deciding; the calculator gives you both numbers for exactly this reason.
Worked Example
A homeowner wants a 30 ft × 4 ft pea gravel walkway at 2.5 inches. Volume: 30 × 4 × (2.5 ÷ 12) = 25 cubic feet = 0.93 cubic yards. Weight: 0.93 × 1.4 = 1.3 tons. With a 10% buffer: order 1.4 tons, or about 50 bags if buying bagged — right at the bulk break-even, so price both options. At $45/ton bulk, that's roughly $63 in material plus delivery, versus about $250 in bags.