Gravel Calculator
Multiply length × width × depth in feet, then divide by 27 to get cubic yards. A 12 × 20 ft driveway 3 inches deep needs 2.22 cubic yards, about 2.7 to 3 tons of crushed stone.
Updated October 15, 2026 · How we calculate
Worked example
A 12 ft × 20 ft parking pad, 3 inches of crushed stone:
- Area: 12 × 20 = 240 square feet
- Depth in feet: 3 ÷ 12 = 0.25 ft
- Volume: 240 × 0.25 = 60 cubic feet
- Cubic yards: 60 ÷ 27 = 2.222 cu yd
- Weight: 2.222 × 2,410 to 2,700 lb ÷ 2,000 = 2.68 to 3 tons
- Bags: 60 ÷ 0.5 = 120 bags of 0.5 cu ft
Source: Caltrans Maintenance Manual, Appendix (2014); Missouri DOT, Highway Maintenance Tables and Conversion Factors
How to choose and how deep
Which gravel
- Crushed stone (#57, 3/4 in.). Angular stone that locks together. The usual pick for driveways and drainage.
- Crushed base (crusher run, road base). Stone mixed down to dust. Packs hard; used under driveways and pavers.
- Pea gravel. Small rounded stones. Comfortable for paths and play areas, but it shifts underfoot.
- River rock. Smooth rounded stone for beds, borders and dry creek beds.
How deep
Driveway: at least 6 inches of gravel for most conditions.
Source: University of Wisconsin–Madison, Gravel PASER Manual (2015)
Under pavers: at least 4 inches of compacted base for a patio or walk, and at least 6 inches for a driveway. Add 2 to 4 inches in cold climates or on wet, weak soil.
Source: ICPI Tech Spec 2 (rev. Feb 2020)
If you will compact it
The calculator gives the loose amount for the depth you type. Stone shrinks when it is packed down: one published spec spreads 8 inches to finish at 6. If your depth is the finished depth, order about a third more.
Source: Penn State Center for Dirt & Gravel Roads, DSA Tech Bulletin (2025)
Quick reference
| Gravel | Lb per cubic yard | Tons per cubic yard | Source |
|---|---|---|---|
| Crushed stone (#57, 3/4 in.) | 2,410 to 2,700 | 1.21 to 1.35 | Caltrans Maintenance Manual, Appendix (2014); Missouri DOT, Highway Maintenance Tables and Conversion Factors |
| Crushed base (crusher run, road base) | 2,550 to 2,700 | 1.28 to 1.35 | Caltrans Maintenance Manual, Appendix (2014) |
| Pea gravel | 2,592 | 1.3 | Vigoro pea gravel bag label (0.5 cu ft, 48 lb) |
| River rock | 2,484 | 1.24 | Pavestone river pebbles bag label (0.5 cu ft, 46 lb) |
Questions people ask
How many tons are in a cubic yard of gravel?
Loose crushed stone weighs about 2,410 to 2,700 pounds per cubic yard, which is 1.21 to 1.35 tons. Rounded stone such as pea gravel is close to that; wet or compacted gravel weighs more.
Source: Caltrans Maintenance Manual, Appendix (2014); Missouri DOT, Highway Maintenance Tables and Conversion Factors
How many bags of gravel make a cubic yard?
A cubic yard is 27 cubic feet, so it takes 54 bags of 0.5 cubic feet.
How much area does one cubic yard of gravel cover?
At 3 inches deep, one cubic yard covers 108 square feet. At 4 inches it covers 81 square feet, and at 6 inches 54 square feet.
How deep should a gravel driveway be?
At least 6 inches of gravel for most conditions. Soft or wet ground needs more.
Source: University of Wisconsin–Madison, Gravel PASER Manual (2015)
Do I need extra gravel if I compact it?
Yes. Loose stone settles when it is compacted: one published spec places 8 inches of aggregate to end up with 6 inches compacted. If the depth you typed is the finished, compacted depth, order about a third more.
Source: Penn State Center for Dirt & Gravel Roads, DSA Tech Bulletin (2025)