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Gravel Driveway Calculator · Free calculator

20x20 Gravel Driveway Calculator

Covering 20' × 20' (400 sq ft) with 4" of gravel takes 5.43 cubic yards — about 7.60 tons — with 10% extra. A full 3-layer driveway build for 20x20 is 19.01 tons. Depths, layers, truck loads and fabric are below.

Quick answer

4" gravel
5.43 yd³
Weight @ 4"
7.60 tons
3-layer driveway (10")
19.01 tons
Tandem truck loads (15 t)
2
Geotextile fabric
49 sq yd
Est. gravel cost @ 4"
$303

▍Gravel Calculator

Material
ft
in
ft
in
in
Waste Factor
$
L = 20' 0"W = 20' 0"D = 4"
Cubic Yards
5.43yd³
incl. 10% waste · Bulk delivery: order 5.50 yd³
Cubic Feet
146.67ft³
Area
400.0sq ft
Weight
7.60tons
Weight
15,210lbs
Gravel bags needed
  • 0.5 cu ft bag (~50 lb) (0.5 ft³ yield)294

Gravel for 20x20 by depth

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

DepthUseCubic yardsTonsTruck loadsBulk est.
2"Top dressing / refresh2.72 yd³3.801$151
4"Top layer (#57 stone)5.43 yd³7.601$303
6"New pad on firm soil8.15 yd³11.411$454
8"New driveway on soft soil10.86 yd³15.212$605

3-layer gravel driveway build for 20x20

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"5.43 yd³7.60
#57 stone (¾"–1") middle4"5.43 yd³7.60
Crusher run / dense grade top2"2.72 yd³3.80
Total10"13.58 yd³19.01

How the math works

  1. Area: 20 ft × 20 ft = 400 sq ft
  2. Volume @ 4": 400 × (4 ÷ 12) = 133.33 cu ft
  3. Add 10%: 133.33 × 1.10 = 146.67 cu ft
  4. Cubic yards: 146.67 ÷ 27 = 5.43 yd³
  5. Tons: 5.43 × 1.4 = 7.60 tons
  6. Truck loads: 19.01 tons ÷ 15 tons per tandem = 2

Trade pro tips

  • At 4" deep, 20x20 takes 7.60 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 20x20 driveway?

At 4" deep: 7.60 tons. At 6": 11.41 tons. A complete 3-layer driveway (4" #3 + 4" #57 + 2" crusher run) is 19.01 tons. All include 10% extra.

How many cubic yards of gravel for 20x20?

2": 2.72 yd³; 4": 5.43 yd³; 6": 8.15 yd³; 8": 10.86 yd³. 20x20 is 400 sq ft.

How many truck loads of gravel for a 20x20 driveway?

A tandem dump truck carries about 15 tons. 20x20 at 4" (7.60 t) is 1 load; the full 3-layer build (19.01 t) is 2 loads.

How much does a 20x20 gravel driveway cost?

Stone alone at 4" is about $303 (~$55/yd³). A 3-layer build runs roughly $747 in material plus 49 sq yd of fabric; delivery and grading are extra.