How to Calculate Gravel
Estimating gravel requires calculating the volume of the area to fill, then converting to weight since gravel is sold by the ton. Coverage depends on the type of gravel and the depth you need.
Volume Formula
Start by calculating the cubic yards of gravel needed for your project area:
Cubic Yards=Lft×Wft×Din1227
Tons Conversion
Convert cubic yards to tons using the density of your chosen gravel type. Most gravel weighs between 1.3 and 1.5 tons per cubic yard:
Tons=Cubic Yards×Densitytons/yd3
Gravel Types Comparison
| Type | Density (tons/yd3) | Best Use |
|---|---|---|
| Pea Gravel | 1.30 | Walkways, patios, pipe bedding |
| Crushed Stone (#57) | 1.40 | Driveways, drainage, backfill |
| Crusher Run | 1.50 | Base layer, road base, compaction |
| River Rock | 1.35 | Landscaping, dry creek beds |
| Marble Chips | 1.45 | Decorative beds, garden borders |
| Lava Rock | 0.50 | Lightweight mulch alternative, fire pits |
Depth Recommendations
- Walkways and patios - 2 to 3 inches of decorative gravel over compacted base
- Driveways - 4 to 6 inches total (3" base layer + 2" top layer)
- Drainage beds - 6 to 12 inches of clean crushed stone
- French drains - 8 to 12 inches surrounding the perforated pipe
Bulk vs. Bagged Cost
Bags Needed=Tons×2000Bag Weightlbs
Bulk delivery is typically 30 to 50% cheaper per ton than buying bagged gravel. For projects needing more than half a ton, bulk is almost always more economical. Most suppliers require a minimum of 1 to 2 tons for delivery.
Drainage Base Requirements
For any paved surface - patios, walkways, or driveways - always install a compacted gravel base layer (crusher run or #57 stone) beneath the finish material. This base prevents settling and improves drainage. Minimum base depth is 4" for foot traffic and 6" for vehicle traffic.Order Extra
Order 10 to 15% more gravel than your calculated amount. Gravel settles and compacts after installation, and you will lose some material at the edges of your project area.