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Gravel Driveway Calculator · Free calculator

12x20 Gravel Driveway Calculator

Covering 12' × 20' (240 sq ft) with 4" of gravel takes 3.26 cubic yards — about 4.56 tons — with 10% extra. A full 3-layer driveway build for 12x20 is 11.41 tons. Depths, layers, truck loads and fabric are below.

Quick answer

4" gravel
3.26 yd³
Weight @ 4"
4.56 tons
3-layer driveway (10")
11.41 tons
Tandem truck loads (15 t)
1
Geotextile fabric
30 sq yd
Est. gravel cost @ 4"
$193

▍Gravel Calculator

Material
ft
in
ft
in
in
Waste Factor
$
L = 20' 0"W = 12' 0"D = 4"
Cubic Yards
3.26yd³
incl. 10% waste · Bulk delivery: order 3.50 yd³
Cubic Feet
88.00ft³
Area
240.0sq ft
Weight
4.56tons
Weight
9,126lbs
Gravel bags needed
  • 0.5 cu ft bag (~50 lb) (0.5 ft³ yield)176

Gravel for 12x20 by depth

240 sq ft, 10% waste. Crushed stone ≈ 1.4 tons/yd³, ~$55/yd³ delivered.

DepthUseCubic yardsTonsTruck loadsBulk est.
2"Top dressing / refresh1.63 yd³2.281$96
4"Top layer (#57 stone)3.26 yd³4.561$193
6"New pad on firm soil4.89 yd³6.841$275
8"New driveway on soft soil6.52 yd³9.131$371

3-layer gravel driveway build for 12x20

The standard US build for a driveway that won’t rut: big stone base, mid-size stone, fines on top.

LayerDepthCubic yardsTons
#3 stone (1"–2½") base4"3.26 yd³4.56
#57 stone (¾"–1") middle4"3.26 yd³4.56
Crusher run / dense grade top2"1.63 yd³2.28
Total10"8.15 yd³11.41

How the math works

  1. Area: 20 ft × 12 ft = 240 sq ft
  2. Volume @ 4": 240 × (4 ÷ 12) = 80.00 cu ft
  3. Add 10%: 80.00 × 1.10 = 88.00 cu ft
  4. Cubic yards: 88.00 ÷ 27 = 3.26 yd³
  5. Tons: 3.26 × 1.4 = 4.56 tons
  6. Truck loads: 11.41 tons ÷ 15 tons per tandem = 1

Trade pro tips

  • At 4" deep, 12x20 takes 4.56 tons — a single dump truck delivery covers it.
  • 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 12x20 driveway?

At 4" deep: 4.56 tons. At 6": 6.84 tons. A complete 3-layer driveway (4" #3 + 4" #57 + 2" crusher run) is 11.41 tons. All include 10% extra.

How many cubic yards of gravel for 12x20?

2": 1.63 yd³; 4": 3.26 yd³; 6": 4.89 yd³; 8": 6.52 yd³. 12x20 is 240 sq ft.

How many truck loads of gravel for a 12x20 driveway?

A tandem dump truck carries about 15 tons. 12x20 at 4" (4.56 t) is 1 load; the full 3-layer build (11.41 t) is 1 load.

How much does a 12x20 gravel driveway cost?

Stone alone at 4" is about $193 (~$55/yd³). A 3-layer build runs roughly $448 in material plus 30 sq yd of fabric; delivery and grading are extra.