How much concrete for a 10x20 driveway?
3.1 cu yd of concrete for a 10x20 driveway pad, at the settings most people start with. Below the calculator are the same numbers for the alternatives you are likely to choose, and what each one does to the total.
Reviewed · Method: measured dimensions, industry coverage rates, rounded up to real package sizes · How the numbers are calculated
Values are pre-filled for this page. Change anything and hit Recalculate.
The answer, and what it is made of
A 20 x 10 ft slab at 5 in thick is 3.1 cu yd of concrete. That is 146 bags at 80 lb each, which is why this size usually goes ready-mix: 146 bags is a long day with a mixer, and the truck arrives at a consistent slump instead of however you happened to mix the fortieth bag.
Planning figure for everything on that list: $1,115 to $1,747, with $1,384 as the realistic middle for the products most people actually buy. These are estimates for budgeting, not quotes. Prices move by region and by season, and the middle figure assumes a mid-range product rather than the cheapest thing on the shelf.
Thickness is the expensive variable: 3.1 cu yd at 5 in becomes 3.7 cu yd at 6 in, a jump of 19%. That extra concrete does less for crack resistance than a properly compacted base, which costs a fraction as much.
What changes if you change one thing
| Change the slab thickness | You buy |
|---|---|
| 4 in, cars only, no frost | 2.5 cu yd |
| 5 in, typical driveway | 3.1 cu yd |
| 6 in, RV or delivery truck | 3.7 cu yd |
Every row is a live calculation, not an estimate. The shaded row is what this page defaults to.
What goes in the cart
| Item | Quantity |
|---|---|
| Concrete mix, 80 lb | 146 bags |
| Concrete mix, 60 lb (alternative) | 195 bags |
| Crushed gravel base | 5.2 tons (100 cu ft) |
| 6 mil vapor barrier | 200 sq ft |
| Form boards + stakes | 60 ft |
| Control joints | 2 runs |
Above 1 cubic yard, call the truck. 146 bags is 11,680 lb to haul and mix before it sets. A short-load fee beats a failed pour.
What this size actually changes
Two hundred square feet at 5 in is 3.1 cubic yards, just past the short-load threshold and therefore the smallest driveway that prices sensibly. The thickness is the part that matters: 4 in over soil is the classic failure, and the difference between 2.5 and 3.1 yards is far less than the cost of replacing a cracked apron in three years.
Figure. 10x20 driveway pad at 5 in thick over a compacted base. Thickness sets the volume; the base sets whether it cracks.
How the quantity is worked out
Concrete is ordered by the cubic yard and sold in bags by weight, and the gap between those two units is where most estimates go wrong. A yard is 27 cubic feet, so a 10x12 slab at 4 in thick is 40 cu ft, or 1.5 cu yd. Rounded to whole yards at the ready-mix plant, that is 1.5 or 2 — and the shortfall shows up as a slab that is an inch thin at one corner.
Thickness is the expensive variable. Going from 4 in to 5 in on the same footprint adds 25 percent to the volume and 25 percent to the bill. Depth of the compacted base is the cheap variable: a proper 4 to 6 in base costs far less than an extra inch of concrete and prevents most of the cracking that a thicker slab would not have fixed anyway.
How to measure this job
Measure the driveway as a series of rectangles, because most are not one shape. The apron at the road, the run beside the house and any turning area usually have different widths, and each has to be counted. Then measure the depth of the existing surface: a driveway replacement often has to match the level of the road and the garage floor.
Thickness and base depth are the two numbers that decide whether it survives a winter. Five inches over 6 in of compacted base is the normal specification for a residential drive; four inches over soil is what fails in the third year.
Mistakes that cost real money
Ordering exactly the calculated volume
Ready-mix is delivered in whole yards and you cannot add half a yard on site. Order 5 to 10 percent over, because spillage, an uneven subgrade and a slightly deeper edge all consume concrete. Running short mid-pour produces a cold joint, which is a permanent weak line.
Four inches of concrete straight onto the subgrade
Residential driveways need 5 in of concrete over a compacted base in most climates. Four inches with no base is the classic failure pattern: hairline cracks in year one, a broken edge in year three, replacement in year eight.
Skipping the base because the driveway is short
A 20 ft run still takes traffic and still moves water. Six inches of compacted base is what spreads the load; without it the slab cracks along the wheel tracks, which is the failure pattern you see on almost every failed driveway.
No fall to the street
A driveway has to shed water somewhere, and if the street is higher than the garage, the answer is a channel drain at the low point, not a flatter slab. Work out the levels before the forms go in, because the slab cannot be re-sloped afterwards.
Frequently asked questions
How many 80 lb bags of concrete make a yard?
Forty-five. An 80 lb bag yields about 0.6 cu ft, and a cubic yard is 27 cu ft. That means a 1.5 cu yd slab needs roughly 68 bags, which is why anything past about one yard usually goes ready-mix: 68 bags is a long day with a mixer and a lot of lifting.
How much concrete for a 10x20 driveway?
At 5 in thick, 3.1 cubic yards. At 4 in, 2.5; at 6 in, 3.7. Order a little over, and expect the ready-mix truck to charge a short-load fee below about 3 yards in many areas.
How much concrete for a 10x20 driveway?
2.5 cubic yards at 4 in, 3.1 at 5 in, 3.7 at 6 in. Five inches over 6 in of base is the normal residential specification, and it is what this page defaults to.
How long before I can park on a new driveway?
Seven days for a car in mild weather, 28 days before anything heavy. Concrete gains strength slowly, and a delivery truck on a three-day-old driveway will leave tyre marks that never come out and may crack the slab.
What will the materials for this cost?
A planning range of $1,115 to $1,747 for everything in the shopping list, with $1,384 as the realistic middle. That is materials only: it excludes labour, delivery, tool hire and disposal of the old surface. Treat it as a budgeting figure, not a quote.