How Much Concrete for a Driveway?
A driveway is ready-mix territory, without exception. Here is the volume by size.
A 20×24 driveway at 5 inches needs 8.15 cubic yards of concrete. That is 220 cubic feet, or 367 bags of 80 lb — which tells you everything about why a driveway is always poured from a truck.
Estimates only. Textured walls, high ceilings, sprayers and major colour changes can all increase the amount you need. Always buy slightly more than the calculation suggests.
Concrete needed by driveway size
| Pour | Volume | Cubic yards | Bags | Cheaper |
|---|---|---|---|---|
| Single drive, 12 x 30 at 5" | 165 cu ft | 6.1 cu yd | 275 × 80 lb | Ready-mix |
| Single drive, 14 x 40 at 5" | 256.7 cu ft | 9.5 cu yd | 428 × 80 lb | Ready-mix |
| Double drive, 20 x 24 at 5" | 220 cu ft | 8.1 cu yd | 367 × 80 lb | Ready-mix |
| Double drive, 24 x 30 at 5" | 330 cu ft | 12.2 cu yd | 550 × 80 lb | Ready-mix |
| Double drive, 24 x 40 at 6" | 528 cu ft | 19.6 cu yd | 880 × 80 lb | Ready-mix |
| Double drive, 24 x 40 at 4" | 352 cu ft | 13 cu yd | 587 × 80 lb | Ready-mix |
10 % waste. A single-car drive is usually 12 to 14 feet wide, a double 20 to 24. Bags are shown to make the point, not because anyone uses them.
Five inches is the minimum for a driveway
A driveway takes cars, delivery vans and occasionally something much heavier. Four inches is not enough.
- 5 inches — the standard for a residential driveway carrying cars and light vans.
- 6 inches — for a driveway that will see regular heavy loads: a caravan, a boat, a work van, or a bin lorry turning on it.
- 4 inches — only for a footpath, patio or shed base. Not a driveway.
Under the slab you need a properly compacted sub-base, usually 4 to 6 inches of crushed stone. A driveway is a structure, and the concrete is only the top layer of it. Most driveway failures are base failures, not concrete failures.
Why a driveway is never done in bags
8.15 cubic yards is 367 bags of 80 lb — nearly 15 tonnes of material. Nobody mixes that by hand, and even if they tried, they could not place it fast enough.
This is the practical limit people miss. Concrete sets in about an hour after mixing. A driveway pour has to be placed, screeded, floated and finished as one continuous operation, or you get cold joints — visible seams where one batch set before the next arrived. On a driveway those joints are weak points, and they look like cracks from day one.
Ready-mix is the only realistic option above roughly 2 cubic yards. Below that, bags are viable for someone fit and patient.
Ordering the truck, and the traps
Ready-mix is ordered in cubic yards, usually in quarter-yard increments, and the supplier will ask how you are placing it.
- Add 5 to 10 % to your calculated volume. Suppliers will usually send a little extra, but you pay for what you order, and a part-load return fee applies to what you send back.
- Access. A standard truck chute reaches roughly 15 to 20 feet. Beyond that you need wheelbarrows, a pump truck, or a conveyor — and a pump adds a significant fixed cost.
- Time. Most suppliers allow a set time on site before charging waiting time. Have your help organised before the truck arrives.
- Weather. Do not pour in frost or in heavy rain. Concrete that freezes before it cures is permanently weakened.
- Joints. A driveway needs control joints every 8 to 12 feet each way, and expansion joints where it meets the garage, the pavement and any steps.
Frequently asked questions
How much concrete for a 20x24 driveway?
About 8.15 cubic yards at 5 inches thick with 10 % waste. That is 220 cubic feet.
How thick should a concrete driveway be?
Five inches for cars and light vans, six inches if it will carry caravans, boats or regular heavy loads. Four inches is not enough for a driveway.
How many bags of concrete for a driveway?
A 20x24 driveway needs 367 bags of 80 lb mix. That is why driveways are always poured from a ready-mix truck.
How much does a concrete driveway cost?
At $165 per cubic yard delivered, the concrete for a 20x24 driveway is about $1,345. Labour, sub-base, formwork and finishing usually cost more than the concrete itself.