Gravel Bed Calculator Formula
Understand the math behind the gravel bed calculator. Each variable explained with a worked example.
Formulas Used
Gravel Volume
cubic_yards = vol_cuft / 27Approximate Weight
tons = vol_cuft / 27 * 1.4Bed Area
area = length * widthVariables
| Variable | Description | Default |
|---|---|---|
length | Length(ft) | 20 |
width | Width(ft) | 10 |
depth_in | Gravel Depth(in) | 4 |
vol_cuft | Derived value= length * width * depth_in / 12 | calculated |
How It Works
Gravel Bed Calculation
Volume (cu ft) = L x W x Depth (ft)
Tons = Cubic Yards x 1.4 (typical for crushed stone)
Gravel weighs roughly 1.3 to 1.5 tons per cubic yard depending on stone type. For drainage beds, use 4 to 6 inches of washed gravel. For decorative paths, 2 to 3 inches is sufficient.
Worked Example
20 x 10 ft gravel path at 4 inches deep.
- 01Volume = 20 x 10 x (4/12) = 66.7 cu ft
- 02Cubic yards = 66.7 / 27 = 2.5
- 03Tons = 2.5 x 1.4 = 3.5 tons
Frequently Asked Questions
What size gravel should I use for a walkway?
Pea gravel (3/8 inch) or fine crushed stone (1/4 to 3/8 inch) works well for paths. Larger stone (3/4 inch) is better for drainage applications.
Do I need landscape fabric under gravel?
Yes, landscape fabric prevents gravel from mixing into the soil below and reduces weed growth. It is especially important for decorative gravel beds.
Ready to run the numbers?
Open Gravel Bed Calculator