Concrete Yardage Calculator

Concrete yardage calculator for rectangular forms. Enter length, width, thickness, and waste to get cubic yards, cubic feet, and a quick 80 lb bag estimate. For thickness guidance, reference the slab thickness guide. For delivery-fee and mix-rate context, review the concrete pricing guide.

Inputs

Tip: Add more waste for irregular forms or thickened edges.

Results

Concrete volume
1.63 yd³
44 ft³
80-lb bags (rough)
73.33
Assumes ~0.6 ft³ yield per 80-lb bag (varies by mix).

FAQ

  • How many yards of concrete do I need? Multiply length × width × thickness and divide by 27, then add waste.
  • How many 80 lb bags equal a yard? Roughly 45 bags per cubic yard at ~0.6 ft³ per bag.
  • Should I order extra? Yes, add 5–10% for spillage, uneven forms, and subgrade voids.
  • Can I use this for slabs and driveways? Yes—any rectangular pour with a consistent thickness.

Assumptions

  • Rectangular form with uniform thickness.
  • Waste accounts for spillage, uneven subgrade, and form variation.
  • 80-lb bag yield is an approximation; check product labels.

Example

A 12 ft × 10 ft pour at 4 inches thick with 10% waste is about 1.63 yd³.

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Concrete Estimating Guide

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