How the math works
Area: 40 ft × 30 ft = 1200 sq ftVolume @ 4": 1200 × (4 ÷ 12) = 400.00 cu ftAdd 10%: 400.00 × 1.10 = 440.00 cu ftCubic yards: 440.00 ÷ 27 = 16.30 yd³Tons: 16.30 × 1.4 = 22.81 tonsTruck loads: 57.04 tons ÷ 15 tons per tandem = 4
Trade pro tips
- At 4" deep, 30x40 takes 22.81 tons — that is more than one tandem dump truck load.
- Build in layers: 4" of #3 (2"–3") stone, 4" of #57, then 2" of crusher run / dense grade on top.
- Lay non-woven geotextile over clay soil first — it stops stone from sinking.
- Crown the driveway ½" per foot so water sheds to the sides.
- Spread with a box blade and compact each layer before the next.
Frequently asked questions
How many tons of gravel do I need for a 30x40 driveway?
At 4" deep: 22.81 tons. At 6": 34.22 tons. A complete 3-layer driveway (4" #3 + 4" #57 + 2" crusher run) is 57.04 tons. All include 10% extra.
How many cubic yards of gravel for 30x40?
2": 8.15 yd³; 4": 16.30 yd³; 6": 24.44 yd³; 8": 32.59 yd³. 30x40 is 1200 sq ft.
How many truck loads of gravel for a 30x40 driveway?
A tandem dump truck carries about 15 tons. 30x40 at 4" (22.81 t) is 2 loads; the full 3-layer build (57.04 t) is 4 loads.
How much does a 30x40 gravel driveway cost?
Stone alone at 4" is about $908 (~$55/yd³). A 3-layer build runs roughly $2,241 in material plus 147 sq yd of fabric; delivery and grading are extra.