Concrete Driveway Calculator
A standard two-car driveway (20×50 ft at 5 inches thick) needs 15.4 cubic yards of concrete — that's one ready-mix truck. Enter your dimensions below for the exact volume, bag count, and cost estimate.
Pro Tips
- →Driveways should be 5-6 inches thick for passenger vehicles
- →Add 10% extra for waste and uneven ground
- →Consider 6-8 inches for heavy vehicles like RVs or trucks
- →A two-car driveway is typically 20 feet wide
- →Allow concrete to cure for 7 days before driving on it
Includes 10% waste factor
That's typically a professional pour. See costs ↓
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Cost Estimate
Estimated material costs for your project
Recommendation: Ready-Mix Concrete
For projects over 1 cubic yard, ready-mix is typically more economical and easier to work with.
764 bags × 80lb
16.98 cubic yards + delivery
1000 sq ft × $3.00–$8.00/sq ft
Prices vary by location and time. Contact local suppliers for accurate quotes.
For general step-by-step instructions, read our complete Driveway Thickness and Driveway Cost.
How to Calculate Driveway Concrete Volume
Driveway concrete is measured in cubic yards. The formula is the same as any slab: length (ft) × width (ft) × (thickness in inches ÷ 12) ÷ 27. The ÷12 converts inches of thickness to feet; the ÷27 converts cubic feet to cubic yards (a cubic yard is 3 ft × 3 ft × 3 ft = 27 cubic feet).
Work a 20×50 ft driveway at 5 inches: 20 × 50 = 1,000 sq ft of surface. Thickness is 5 ÷ 12 = 0.417 ft. So 1,000 × 0.417 = 417 cubic feet, and 417 ÷ 27 = 15.43 cubic yards before waste. Add 10% and you order 17 cubic yards (rounded up to whole yards, as most ready-mix suppliers require). For a step-by-step walkthrough of the math, see our how to calculate concrete guide.
Unlike a square patio, driveways are often long, narrow, or L-shaped around a garage. Break any irregular driveway into rectangles, calculate each separately, and sum the cubic yards. Never average an L-shape into one big rectangle — you will over- or under-order.
Cubic Yards by Common Driveway Size
The table below covers the most common residential driveway footprints at 4, 5, and 6 inches. Volumes are calculated with the formula above; bag counts include a 10% waste factor at roughly 45 bags of 80-lb mix per cubic yard.
| Driveway Size | Surface | 4 in | 5 in | 6 in |
|---|---|---|---|---|
| 1-car (10×20 ft) | 200 sq ft | 2.47 cu yd | 3.09 cu yd | 3.70 cu yd |
| 2-car (20×20 ft) | 400 sq ft | 4.94 cu yd | 6.17 cu yd | 7.41 cu yd |
| 2-car long (24×40 ft) | 960 sq ft | 11.85 cu yd | 14.81 cu yd | 17.78 cu yd |
| RV / oversized (12×40 ft) | 480 sq ft | 5.93 cu yd | 7.41 cu yd | 8.89 cu yd |
These figures are before waste. Multiply by 1.10 to get your order quantity. A 2-car long driveway at 6 inches, for example, jumps from 17.78 to 19.56 cubic yards with waste — that is two full ready-mix trucks, so coordinate the pour and finishing crew accordingly.
Choosing Driveway Thickness by Vehicle Load
Thickness is the single most important structural decision for a driveway, because it drives both load capacity and total volume. Thicker is not always better — every extra inch is real money and real concrete.
| Use Case | Recommended Thickness | Standard / Note |
|---|---|---|
| Foot traffic, light golf cart | 4 in | IRC R506.2.3 sets 3.5 in as the residential slab-on-ground minimum |
| Passenger cars and SUVs | 5 in | Most common residential spec |
| Pickups, occasional heavy loads | 5–6 in | Thicken edges to 6–8 in where wheels track |
| Heavy trucks, RVs, trailers | 6 in | Add reinforcement; consider ACI 330 guidance for parking/drive areas |
| Constant commercial loads | 6–8 in | Engineered design recommended |
For cars and SUVs, 5 inches is the practical residential standard. A 4-inch slab is acceptable for passenger vehicles on a well-compacted base but offers little margin; 5 inches is the safer default. The IRC R506.2.3 minimum (3.5 in) applies to interior slabs-on-ground, not vehicle-loaded exterior driveways — so treat it as a floor, not a target. For a deeper comparison, see our driveway thickness guide and the 4 vs 6 inch guide.
Why You Add 10% for Waste
The formula gives a theoretical volume. Real driveways always need more. A 10% waste allowance covers:
| Source of Loss | Typical Impact |
|---|---|
| Uneven or over-excavated subgrade | 3–6% extra fill |
| Spillage during placement | 1–2% |
| Material left in the truck/chute | 1–2% |
| Slight over-thickness at form edges | 1–3% |
For a 6.17 cubic yard pour (20×20 at 5 in), 10% waste means ordering 6.79 cubic yards. Running short mid-pour is far costlier than a little excess: a cold joint forms where fresh concrete meets set concrete, creating a permanent weak line. On a poorly graded subgrade, bump the allowance to 12–15%.
Ready-Mix vs. Bagged: The Crossover Point
Driveways almost always call for ready-mix delivery. The crossover where bags stop making sense is around 1 cubic yard, which equals roughly 45 bags of 80-lb mix — about 3,600 lbs you would mix by hand. Every common driveway size blows past that.
| Driveway Size (5 in) | Cubic Yards (+10%) | 80-lb Bags | Practical Method |
|---|---|---|---|
| 1-car (10×20 ft) | 3.40 cu yd | 153 bags | Ready-mix |
| 2-car (20×20 ft) | 6.79 cu yd | 306 bags | Ready-mix |
| RV pad (12×40 ft) | 8.15 cu yd | 367 bags | Ready-mix |
| 2-car long (24×40 ft) | 16.30 cu yd | 733 bags | Ready-mix (2 trucks) |
Even the smallest 1-car driveway needs over 150 bags — far beyond what is sane to hand-mix before the first batches set. A standard ready-mix truck carries about 10 cubic yards, so most single-section driveways fit in one truck and the largest need two. For the cost trade-off, see our ready-mix vs bagged guide.
Reinforcement and Measuring Sloped or Flared Driveways
Reinforcement does not change your concrete volume but should be planned alongside it. Wire mesh (6×6 W1.4/W1.4 welded wire fabric) is the residential minimum; place it on 1.5-inch chairs at mid-depth, since mesh lying on the subgrade does nothing. For 6-inch driveways carrying trucks or RVs, upgrade to #4 rebar on 18-inch centers both ways.
Sloped driveways (toward a garage or street for drainage) have the same volume as a flat driveway of equal average thickness — a 2% drainage slope does not meaningfully change cubic yards. What does add concrete is a thickened apron at the street and flared entries that widen near the road. Measure flares as separate triangles or trapezoids: a triangular flare is ½ × base × height in square feet, then multiply by thickness-in-feet ÷ 27 for cubic yards. Add those to your rectangle totals before applying the waste factor.
Ready to pour? Enter your dimensions in the calculator above for an exact volume, bag count, and truck count. For full pour technique, see how to pour concrete. For installed pricing, use the Concrete Driveway Cost Calculator or the broader Concrete Cost Calculator.