How Much Concrete Do I Need? A Simple Guide
One of the most common questions we get at UNO Concrete is: "How much concrete do I need?" Order too little and your pour stops mid-job. Order too much and you're paying for material that ends up in a dumpster. Getting the estimate right — and then adding a smart overage — is the key to a smooth delivery day.
The Basic Formula: Length × Width × Depth
Concrete is measured in cubic yards. One cubic yard equals 27 cubic feet. To find your volume, multiply the length (feet) × width (feet) × depth (feet), then divide by 27.
Formula: (Length ft × Width ft × Depth ft) ÷ 27 = Cubic Yards
For example, a 20 ft × 20 ft patio poured at 4 inches thick (0.33 ft): 20 × 20 × 0.33 ÷ 27 = 4.9 cubic yards. Round up to 5 yards and add your waste factor on top.
Common Depths by Project Type
- Driveways: 4 inches minimum, 6 inches for heavy vehicles
- Patios and walkways: 4 inches
- Garage floors: 4–6 inches
- Footings: varies by load — typically 8–12 inches deep, 16–24 inches wide
- Foundation walls: 8–10 inches
- Retaining walls: depends on height and design
Why You Should Always Order Extra
Ground is never perfectly flat or level. Low spots, soft areas, and subgrade irregularities all consume more concrete than your calculation assumes. A 5–10% overage is standard practice for most residential pours.
For example, if your calculation comes to 8 cubic yards, order 8.5 to 9 yards. The cost of an extra half yard is far less than the cost of a second delivery charge — or worse, a cold joint in your slab because you ran short.
Rule of thumb: Add 5–10% to your calculated volume for waste, subgrade variation, and spillage. On uneven or soft ground, lean toward 10%.
Using Our Online Calculator
UNO Concrete's homepage includes a free concrete calculator. Enter your dimensions and it instantly shows your cubic yard estimate. Use it as your starting point, then add your overage before you call.
Minimum Load Sizes
Most ready-mix trucks carry 8–10 cubic yards. If your project is smaller, ask about short-load fees. For very small pours (under 1 yard), bagged concrete may be more economical — but for anything larger, ready-mix saves time, labor, and produces a more consistent mix.
When in Doubt, Call Us
Our team at UNO Concrete has helped thousands of contractors and homeowners across the Charlotte area get their estimates right. Give us your dimensions and we'll walk you through the math, recommend the right PSI mix, and schedule delivery on your timeline.
Ready to Order Concrete?
Get a free quote or call us — we'll help you get the right mix and the right amount for your project.