Driveway cost estimate
18x20 Concrete Driveway Cost
A 18 ft × 20 ft concrete driveway is 360 square feet. At a standard 5-inch thickness it needs about 6.11 cubic yards of concrete (with 10 % waste) and costs roughly $2,160 – $5,400 installed with a plain broom finish.
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Material & Cost Breakdown
| Metric | Value | Notes |
|---|---|---|
| Square footage | 360 sq ft | 18 ft × 20 ft |
| Thickness | 5 in | Standard for vehicle traffic |
| Concrete volume | 5.56 yd³ | Before waste |
| Order volume (10% waste) | 6.11 yd³ | Ready-mix ordering target |
| 80 lb bags needed | 275 bags | Including waste |
| 60 lb bags needed | 367 bags | Including waste |
| Ready-mix material cost | $794 – $1,008 | ~$130–$165 per yard delivered |
| Installed cost (broom) | $2,160 – $5,400 | $6–$15 per sq ft |
* Installed cost assumes a standard broom finish, easy site access, and a prepared sub-base. Decorative finishes, tear-out, poor soil, or pump-truck access will move the price higher.
18x20 Driveway Cost by Thickness
Thickness is the single biggest lever on how much concrete a 18x20 driveway needs. A 4-inch pour suits patios and light foot traffic; step up to 5–6 inches for driveways, garages, shops, and anything carrying vehicles or heavy equipment. Each extra inch adds concrete volume and a little labor.
| Thickness | Concrete (10% waste) | Installed cost | Typical use |
|---|---|---|---|
| 4 in | 4.89 yd³ | $2,160 – $5,400 | Patios, walkways, light foot traffic |
| 5 in (standard) | 6.11 yd³ | $2,160 – $5,400 | Driveways, standard garages |
| 6 in | 7.33 yd³ | $2,376 – $5,616 | Shops, RV pads, heavy equipment |
How We Calculated It
- Area: 18 ft × 20 ft = 360 sq ft
- Volume: 360 sq ft × (5 in ÷ 12) = 150.0 cu ft ÷ 27 = 5.56 yd³
- With 10% waste: 5.56 × 1.10 = 6.11 yd³
- Bags (80 lb): 6.11 × 27 ÷ 0.60 cu ft/bag ≈ 275 bags
FAQs
How much does a 18x20 concrete driveway cost?
A 18x20 (360 sq ft) concrete driveway costs roughly $2,160 to $5,400 installed with a broom finish in 2026. Decorative finishes, tear-out, and site prep can raise the price.
How many cubic yards for a 18x20 driveway?
At 5 inches thick, a 18x20 driveway needs about 5.56 cubic yards before waste and 6.11 yards after a 10% ordering allowance.
How many 80 lb bags for a 18x20 driveway?
You would need about 275 bags of 80 lb concrete (including 10% waste). Above roughly one cubic yard, ready-mix is usually cheaper and easier than bags.
How much does a 18x20 driveway cost at 6 inches thick?
A 6-inch 18x20 driveway needs about 7.33 cubic yards of concrete and typically runs $2,376 to $5,616 installed. The thicker pour adds concrete volume, so it costs more than the standard 5-inch slab but resists cracking under vehicles and heavy loads.
Planning Your 18x20 Pour
When preparing to pour a 18 ft × 20 ft concrete driveway, proper planning is essential to keep your project on budget. The dimensions directly determine the total square footage, which in turn dictates the amount of labor, forming materials, and finishing time required.
The thickness is equally important. While 5 inches is standard for this type of driveway, increasing the thickness by just one inch will significantly increase the total cubic yards of concrete needed. Always ensure your sub-base is properly compacted and leveled; an uneven base can lead to thick spots that consume more concrete than your initial estimate predicted. Lastly, ordering with a 10% waste margin is a standard industry practice to account for minor spills, uneven ground, and the small amount of concrete left inside the delivery truck.