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Concrete Yardage Calculator

Calculate exactly how much concrete you need for any slab — patios, driveways, garage floors, and more. Get cubic yards, bag counts, and a complete shopping list.

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Calculate cubic yards of concrete for slabs, footings, walls, and any custom dimensions — with delivery cost guidance.

Concrete Yard Quick Reference Table

Slab Size 4-inch Slab 6-inch Slab Order As
10×10 ft1.36 cu yd2.04 cu yd1.5 or 2.25 yd (short-load)
10×20 ft2.71 cu yd4.07 cu yd3 or 4.25 yd
12×20 ft (driveway)3.26 cu yd4.89 cu yd3.5 or 5 yd
20×20 ft (garage)5.43 cu yd8.15 cu yd6 or 8.5 yd
20×40 ft (RV pad)10.86 cu yd16.30 cu yd11 or 16.5 yd (2 trucks)

All values include the 10% wastage buffer. Most ready-mix plants order in 0.25-yard increments, so you cannot order exactly 1.36 yards — round up to 1.5. The extra 0.14 yard costs about $22 but eliminates the risk of running out mid-pour.

Ready-Mix Truck Capacity and Short-Load Fees

Standard ready-mix trucks carry 8-10 cubic yards. Smaller trucks (called "mini-mix" or "mud-mixer" trucks) carry 1-4 yards but cost more per yard delivered. Understanding the truck pricing tiers:

  • Under 1 yard: Plants typically refuse. Use bags or rent a mini-mixer truck.
  • 1-2 yards: $200-275 per yard (includes short-load surcharge). Mini-mix or "trailer-haul" services available in some areas.
  • 3-5 yards: $140-180 per yard. Standard pricing tier. Short-load fee of $50-100 usually waived above 3 yards.
  • 6-10 yards: $130-165 per yard. Sweet spot for residential driveways.
  • 10+ yards: May require 2 trucks. Pricing similar to 6-10 yard range, but coordinate truck timing — second truck arrives 15-30 minutes after first.

Additional fees that show up on the invoice: Saturday delivery (+$50-100), after 4pm delivery (+$50), wash-out fee ($25-50 if you do not have a designated wash-out spot), and pump truck if needed ($250-500 for hard-to-reach pours).

Calculating Yardage for Non-Rectangular Shapes

For irregular shapes, break the pour area into rectangles and add the volumes. For circular columns or sonotubes: Volume = π × radius² × depth, then divide by 27 to convert to cubic yards.

Examples for common circular pours (cu yd):

  • 10-inch sonotube × 4 ft deep: 0.08 cu yd (need 0.1 yd order)
  • 12-inch sonotube × 4 ft deep: 0.12 cu yd
  • 12-inch sonotube × 8 ft deep: 0.23 cu yd
  • 8-foot diameter circle, 4 inch deep: 0.62 cu yd
  • 12-foot diameter circle, 4 inch deep: 1.40 cu yd

For multiple deck footings or sonotubes, calculate one and multiply. For complex L-shapes or pour designs with varying depths, break into rectangles, calculate each, and sum.

Frequently Asked Questions

How do I calculate concrete yardage?
Multiply length × width × thickness (all in feet — convert inches by dividing by 12). The result is cubic feet. Divide cubic feet by 27 to get cubic yards. Always add 10% for wastage. For a 10×20 patio at 4 inches thick: 10 × 20 × 0.333 = 66.67 cu ft ÷ 27 = 2.47 cu yd × 1.10 = 2.72 cu yd to order.
What is the minimum order for ready-mix concrete?
Most plants require a 3 cubic yard minimum. Under 3 yards triggers a "short-load fee" of $50-150. Some plants will deliver as little as 1 yard with a higher short-load charge ($150-250 added). Below 1 yard, you are generally better off using bagged concrete from Home Depot or Lowe's.
How much does 1 yard of concrete cost in 2026?
Standard 3000 PSI ready-mix concrete runs $140-$180 per cubic yard in most US metro areas. High-strength 4000 PSI adds 15-20%. Add fees: short-load ($50-150 under 3 yards), fuel surcharge ($10-30), Saturday delivery ($50-100), pump truck ($250-500 if needed). Total installed cost for a 3-yard order typically runs $500-700.
How many bags of concrete equal 1 cubic yard?
You need approximately 45 bags of 80-lb concrete, 60 bags of 60-lb, or 90 bags of 40-lb to equal 1 cubic yard. With the 10% wastage buffer included, the math is: 1 cubic yard = 1 cu yd × 1.10 × yield per bag. An 80-lb bag yields 0.60 cu ft, so 27 ÷ 0.60 = 45 bags pre-waste; 45 × 1.10 = 50 bags with buffer included.
Should I order an extra yard of concrete just in case?
For pours under 5 yards: order 10% over your raw math (the wastage buffer this calculator already builds in). For pours over 5 yards: order exact rounded math — the buffer is already substantial in absolute volume. Returning unused concrete costs $50-100 in disposal fees at most plants. Running short is much worse — a cold joint where you ran out and re-poured later creates a permanent structural weak point.
Related Calculators
→ Yard Calculator→ Cubic Yards Calculator→ Cost Calculator→ Slab Calculator