Road Base Calculator
Estimate how much road base your project needs. Enter the area and depth to get cubic yards, tons and an optional cost.
Picks a typical depth & material — tweak anything below.
For a 20 × 10 feet area at 2 in deep, order about 1.36 cubic yards (2.52 US tons) of class 5 / road base.
All units & details ▾
- Coverage area
- 200 ft²
- Cubic feet
- 36.7 ft³
- Cubic meters
- 1.04 m³
- Metric tons
- 2.28 t
- Total weight
- 5,036 lb
- Density used
- 2,200 kg/m³
Estimates only. Densities vary by moisture, compaction and supplier — confirm quantities before ordering.
What is road base?
Road base — also called Class 5, crusher run, or 3/4" minus — is crushed stone blended with a range of sizes down to fine stone dust. That mix is engineered to compact into a dense, hard, load-bearing layer.
What is road base used for?
It's the go-to sub-base under driveways, patios, roads, sheds and concrete slabs. The fines fill the gaps between larger stones so the whole layer locks up solid when compacted.
How much does road base weigh?
A cubic yard of road base weighs about 1.85 US tons — roughly 2200 kg/m³, or about 137 lb/ft³. Moisture and compaction shift this, so the calculator applies this density and lets you change it in the extra options if your supplier quotes a different figure.
Coverage by depth
| Depth | Coverage per ton | Coverage per cubic yard |
|---|---|---|
| 1 inch | ~175 sq ft | 324 sq ft |
| 2 inches | ~87 sq ft | 162 sq ft |
| 3 inches | ~58 sq ft | 108 sq ft |
| 4 inches | ~44 sq ft | 81 sq ft |
| 6 inches | ~29 sq ft | 54 sq ft |
Based on about 2200 kg/m³. Actual coverage varies with compaction and moisture.
Common mistakes to avoid
- Guessing the depth. Too shallow and the material shifts and shows the ground beneath. Most surface layers want 2–4 inches; load-bearing bases are built up thicker.
- Forgetting to convert inches to feet. Depth is quoted in inches but volume math is in feet — 4 inches is 0.33 ft, not 4. The calculator handles this, but hand estimates often don't.
- Skipping the waste allowance. Ground is never perfectly flat and material settles once it's placed. Order 5–10% extra so a small shortfall doesn't trigger a second delivery.
- Using the wrong density. Each material weighs differently, so tonnage can be off by 20%+ if you use a generic figure. Pick the right material and adjust the density if your supplier differs.
- Buying bags for a big job. Bagged material costs far more per cubic yard than bulk. Past roughly one cubic yard, a bulk delivery is almost always cheaper.
Frequently asked questions
How thick should road base be?+
4 inches of compacted road base is typical under a residential driveway or patio; heavier use or soft ground calls for 6 inches or more, compacted in layers.
Road base or #57 gravel?+
Road base has fines and compacts into a hard surface — use it for load-bearing bases. #57 is clean with no fines and drains freely — use it for drainage or a loose top layer.