How to use it
- Enter length, width (ft) and depth (in).
- Input the expected waste percentage.
- Click Calculate to see volume in cubic yards and total with waste.
The Readymix Calculator turns the basic dimensions of your slab into the exact amount of ready‑mix concrete you need, expressed in cubic yards. You tell the tool the length and width in feet, the depth in inches, and how much waste you expect. The calculator first converts the depth to feet, multiplies length × width × depth to get cubic feet, then divides by 27 to switch to cubic yards. Finally it applies your waste percentage as a multiplier, giving you the total yards you should order. Knowing the precise yardage prevents over‑ordering, which saves money and reduces site clutter, and avoids shortfalls that can delay a project. The results appear instantly, so you can adjust dimensions or waste allowance on the fly and see the impact immediately.
Pro tips
- Add 5‑10% waste for typical residential pours.
- Round up to the nearest 0.1 cubic yard to match supplier minimums.
- Order a little extra if you anticipate changes or uneven subgrade.
- Double‑check that depth is entered in inches, not feet.
Real-life examples
- A homeowner planning a 12 ft × 16 ft patio 4 in deep.
- A contractor estimating concrete for a 30 ft × 45 ft warehouse floor with 6 in depth.
- A landscape designer sizing a garden path 8 ft wide, 100 ft long, 3 in deep.
Case study
Mike needed to pour a 20 ft × 30 ft slab 5 in thick for his garage. Using the calculator, he entered the dimensions and a 7% waste factor, getting 13.2 cu yds total. He ordered 13.5 cu yds, avoiding a costly shortage and saving $200 by not over‑ordering.