Preset dimensions
Common project sizes
What this concrete slab calculator calculates
A slab estimate starts with the plan area and the placed thickness. A 10 × 10 ft slab at 4 in is 33.33 ft³ before waste, or 1.23 yd³.
Formula
Length × width × thickness ÷ 12 = cubic feet; cubic feet ÷ 27 = cubic yards; volume ÷ the product's bag yield = bags.
Worked example
For 10 × 10 ft at 4 in, 10 × 10 × 4 ÷ 12 = 33.33 ft³. With 10% waste, the order is 36.67 ft³, or 1.36 yd³ and 62 80 lb bags at 0.60 ft³ per bag.
Ordering decision
Order ready-mix when the bag count is beyond a practical hand-mix job. Confirm the current yield on the product sheet.
The page cites the applicable Uzi Tools reference table beside the calculator. Product labels, current editions, local code, and a licensed professional govern structural, electrical, and life-safety work.
How to use it
- Enter the measured dimensions and keep the displayed units beside each field.
- Review the concrete slabs by cubic yard or bag result and the substituted formula before ordering.
- Adjust waste for the layout, cut pattern, product package, and site conditions.
- Copy or print the material list, then verify the cited product data and local requirements.
Concrete slabs by cubic yard or bag
Use this construction concrete calculator for a slab or pad, not aquarium gravel or another fill material. Enter the formed length, width, thickness, and waste allowance, then compare cubic yards with bag counts before choosing a supplier.
Limits and professional review
Measurements, product yield, waste, moisture, and site conditions can change the order quantity. Local code and a licensed professional govern structural and electrical work.