Gravel base for driveway calculator
Figure the compacted gravel sub-base that goes under a poured driveway: enter the area and depth and get cubic yards and tons, including an allowance for compaction so you order enough.
Calculator
600 sq ft of sub-base at 4" is about 8.15 yd³ (11.4 tons) including 10% compaction.
Formula
Gravel volume is area times depth, converted to cubic yards, with a compaction allowance; weight uses a labeled density:
yd³ = area × (depth in ÷ 12) ÷ 27 × (1 + compaction)tons = yd³ × 1.4
The 1.4 tons per cubic yard is a labeled typical for compacted crushed stone; the compaction allowance covers the volume lost when the base is tamped down. Both are user-adjustable planning values.
Worked example
600 sq ft at 4″ deep with a 10% compaction allowance:
- Loose volume: 600 × (4 ÷ 12) ÷ 27 = 200 ÷ 27 = 7.41 yd³
- With compaction: 7.41 × 1.10 = 8.15 yd³
- Weight: 8.15 × 1.4 = 11.4 tons
Order about 8.15 cubic yards (roughly 11.4 tons) of gravel for the base.
Sizing the sub-base under a driveway
A compacted gravel sub-base spreads the load and gives the slab a stable, well-draining bed. Residential concrete driveways commonly sit on 4–6″ of compacted crushed stone; deeper bases suit soft soils or heavy vehicles. This is a quantity for ordering material, not a soil-engineering design — a licensed engineer sizes the base for load-bearing or problem soils.
Gravel is sold by the ton or the cubic yard depending on the supplier, so the tool reports both. Densities vary by stone type and moisture, so treat the 1.4 tons/yd³ figure as a labeled planning typical and confirm with your supplier. Ordering a little extra avoids a second delivery if the subgrade is uneven.
Reference table
Gravel for a 600 sq ft driveway by depth (10% compaction, labeled 1.4 tons/yd³):
| Depth | Volume | Weight |
|---|---|---|
| 4″ | 8.15 yd³ | 11.4 tons |
| 5″ | 10.19 yd³ | 14.3 tons |
| 6″ | 12.22 yd³ | 17.1 tons |
Labeled planning typicals — confirm density and depth with your supplier and site.