Gravel driveway calculator
A 20 ft by 10 ft gravel driveway with a 4-inch compacted top layer of gravel over a 12-inch compacted base layer of gravel (layer thicknesses from Maine DEP's gravel road manual; no driveway-specific document was found) needs 2.47 compacted cubic yards of gravel for the top layer (about 3.95 tons, 2.74 loose cubic yards to order) and 7.41 compacted cubic yards of gravel for the base layer (about 11.85 tons, 8.22 loose cubic yards to order): about 15.8 tons in all.
0 uses the published 3,200 lb/yd³
Optional; 0 leaves cost out
0 uses the published 3,200 lb/yd³
Optional; 0 leaves cost out
A 20 ft by 10 ft area needs 2.47 compacted cubic yards of gravel for the top layer (3.95 tons) and 7.41 compacted cubic yards of gravel for the base layer (11.85 tons): 15.8 tons in all. Loose material takes more room before it is compacted: order about 2.74 loose cubic yards of gravel and 8.22 loose cubic yards of gravel.
- Top layer: gravel
- 2.47 yd³ compacted · 3.95 t
- Top layer: loose to order
- 2.74 yd³ (× 1.11, Maine DEP)
- Base layer: gravel
- 7.41 yd³ compacted · 11.85 t
- Base layer: loose to order
- 8.22 yd³ (× 1.11, Maine DEP)
- Total cubic yards
- 9.88
- Total cubic feet
- 266.7
- Total tons
- 15.8
- Total pounds
- 31,605
- To order, rounded up to the half yard
- 3 + 8.5 yd³
How it is calculated
- Area = 20 ft × 10 ft = 200 sq ft.
- Top layer: 200 sq ft × 4 in ÷ 12 = 66.67 cu ft ÷ 27 = 2.469 yd³; × 3,200 lb/yd³ ÷ 2,000 = 3.95 tons.
- Top layer loose: 2.469 yd³ × 1.11 = 2.74 yd³; rounded up to 3 yd³.
- Base layer: 200 sq ft × 12 in ÷ 12 = 200 cu ft ÷ 27 = 7.407 yd³; × 3,200 lb/yd³ ÷ 2,000 = 11.85 tons.
- Base layer loose: 7.407 yd³ × 1.11 = 8.22 yd³; rounded up to 8.5 yd³.
How to calculate gravel for a driveway
Each layer of a gravel driveway is worked out on its own, because the layers differ in thickness and can differ in material. The worked numbers use the calculator's defaults: a 20 ft by 10 ft gravel driveway with 4 inches of top layer and 12 inches of base layer.
Step 1: area in square feet
Rectangle: length × width
Circle: π × diameter² ÷ 4
Triangle: base × height ÷ 2
Example 20 ft × 10 ft = 200 sq ft
Split an irregular area into rectangles, circles and triangles and add their areas.
Step 2: cubic yards of each layer
Cubic yards = area in sq ft × layer thickness in inches ÷ 324
The thickness is the finished thickness: compacted for a base, as placed for bedding sand
Example Top layer (gravel): 200 × 4 ÷ 324 = 2.469 yd³
Example Base layer (gravel): 200 × 12 ÷ 324 = 7.407 yd³
Step 3: tons of each layer
Tons = cubic yards × pounds per cubic yard ÷ 2,000
A compacted layer uses the published weight of a compacted cubic yard, or the loose weight × the published loose factor when no compacted weight is published
Example Top layer (gravel): 2.469 × 3,200 lb per compacted cubic yard ÷ 2,000 = 3.95 tons
Example Base layer (gravel): 7.407 × 3,200 lb per compacted cubic yard ÷ 2,000 = 11.85 tons
Step 4: loose cubic yards to order
Loose cubic yards = compacted cubic yards × published loose cubic yards per compacted cubic yard (low–high)
Example Top layer (gravel): 2.469 × 1.11 = 2.74 loose cubic yards
Example Base layer (gravel): 7.407 × 1.11 = 8.22 loose cubic yards
Loose stone takes more room before it is rolled; the factor comes from the document named with it.
Layer thickness from published guides
The default thicknesses are finished, compacted layers (layer thicknesses from Maine DEP's gravel road manual; no driveway-specific document was found).
| Use as published | Layer | Thickness, in | Source |
|---|---|---|---|
| Gravel road surface layer, compacted | Top layer | 4–6 | Maine Department of Environmental Protection and Kennebec County Soil and Water Conservation District |
| Gravel road base layer, compacted | Base layer | 12–18 | Maine Department of Environmental Protection and Kennebec County Soil and Water Conservation District |
Weight of a compacted layer by material
A compacted layer weighs more per cubic yard than the loose stone delivered for it. The tons in the result use the published weight of a compacted cubic yard where a document gives one, otherwise the loose weight times a published compaction factor. A compacted weight is never multiplied by the factor again; the factor only gives the loose cubic yards to order.
- Gravel: 3,200 lb per compacted cubic yard (Maine DEP); about 1.11 loose cubic yards per compacted cubic yard (Maine DEP).
- Crusher run: 3,770 lb per compacted cubic yard, the middle of Wisconsin DOT research (WHRP)'s 1.79–1.98 tons per cubic yard for “Dense Graded Base 1¼ in”; about 1.34–1.52 loose cubic yards per compacted cubic yard (Wisconsin DOT research (WHRP)).
Driveway gravel layers
A gravel driveway is built in layers: a thicker base that carries the load and drains, and a top course of smaller, well-graded stone that packs into a driving surface. Each layer is calculated separately because the materials differ in weight.
The thicknesses are finished, compacted thicknesses. The tons use the published weight of a compacted cubic yard of each material where a document gives one, and otherwise its loose weight times a published compaction factor. Loose stone takes more room before it is rolled, so where a document gives the loose volume per compacted yard, the result also shows the loose cubic yards to order.