Road Base Calculator
Road base (Class 5 / crusher run) is crushed stone blended with fines that compacts into a hard, load-bearing layer — the go-to sub-base for driveways, patios and slabs. Work out exactly how much you need below.
Sets a typical depth — tweak anything below.
For a 20 ft × 10 ft area at 2 in deep, order about 1.36 cubic yards (2.52 US tons) of class 5 / road base.
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.
Is caliche the same as road base?
In Texas and across the Southwest, caliche is what a lot of people mean when they say road base. It isn't crushed stone — it's a natural soil that calcium carbonate has cemented into a soft rock, dug from a local pit rather than run through a crusher. Spread damp and compacted, it packs into a hard, drivable surface for driveways, ranch roads, and shed and tank pads, and it's usually the cheapest base you can buy in those regions because it comes from down the road instead of a quarry. The trade-offs are real: caliche throws white dust all summer, can go slick and greasy in a hard rain, and varies from pit to pit in how much clay it carries — the more clay, the softer it gets when wet. Crushed road base costs more and is far more consistent. For estimating, treat caliche like road base: it lands in the same 1.5–1.9 tons per cubic yard range, so the Road base setting above gets you close, and you can enter your pit's own weight per yard in the density field if you want it exact.
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.
Is road base the same as crusher run or 3/4 minus?+
Effectively yes — 'Class 5,' 'crusher run,' '3/4 minus,' and 'road base' are regional names for the same idea: crushed stone with all the sizes down to stone dust left in, so it compacts into a hard, dense layer. The exact spec varies a little by area and quarry, so when you order, describe what it's for ('base for a driveway') and confirm it has fines and compacts.
Can road base be the final driveway surface?+
Yes — plenty of rural driveways are compacted road base and nothing else, because it packs into a firm, drivable surface. It won't look as tidy as a clean decorative stone and it can wash a bit on slopes, but it holds up. For a nicer finish, use road base as the compacted base and top it with an inch or two of #57 or a decorative gravel.
Is caliche the same as road base?+
It fills the same job but it isn't crushed stone. Caliche is a natural desert soil cemented together by calcium carbonate, dug straight from a pit across Texas, New Mexico, Arizona and Nevada, and sold cheap as base for driveways, ranch roads and pads. It packs hard when it's damp and rolled. The catches: it's dusty when dry, it can turn slick and greasy in heavy rain, and quality swings a lot from pit to pit — crushed road base is more consistent, caliche is usually cheaper and local.
How much does caliche weigh per cubic yard?+
Figure roughly 1.5 to 1.9 US tons a cubic yard — the same ballpark as crushed road base, which is why you can use the Road base setting above for a caliche estimate. The spread is wide because moisture and how much clay and fines the pit run carries both move the number. If you want a tight figure, ask your pit for pounds per yard and type it into the density field in the extra options.