How to Calculate Gravel for a Driveway

Step-by-step

1. 1

   Measure the area

   Length × width in feet gives square footage. For a curved drive, break it into rectangles and add them together.

2. 2

   Decide total depth

   A residential gravel drive needs at least 8" of stone in three layers: 4" of #3, 3" of #57, and 1" of top dressing. Skimp on depth and you'll get ruts within a year.

3. 3

   Convert to tons

   Formula: (length × width × depth in feet) ÷ 21.6 = tons. Example: a 12x40 ft drive at 8" (0.667 ft) deep needs (12 × 40 × 0.667) ÷ 21.6 ≈ 15 tons. Use the BuildMate Gravel Calculator to skip the math.

4. 4

   Excavate and lay fabric

   Strip topsoil down to firm subgrade. Lay woven landscape fabric to keep gravel from sinking into the subgrade over time.

5. 5

   Place and compact in lifts

   Never dump the full depth at once. Spread each layer, compact with a plate compactor, then add the next. Compaction is what separates a driveway from a pile of rocks.

Safety note: this guide is educational. Always follow local building codes, pull required permits, and hire a licensed pro for structural, electrical, gas or plumbing work when in doubt.