How to use it
- Enter length in feet, width in feet, and thickness in inches.
- Click the Calculate button.
- Read the cubic feet, cubic yards, and bag count results.
What it does – The calculator takes the length, width and slab thickness you enter and instantly gives you three numbers: total cubic feet, cubic yards, and the number of 80‑lb bags needed. Knowing cubic yards helps you order from a ready‑mix plant, while bag count is essential for DIY pours. Why it matters – Ordering too little means costly delays; ordering too much wastes money and material. How to read the results – One cubic yard equals 27 cubic feet. Divide the cubic‑feet result by 27 to see the ready‑mix volume. Divide cubic feet by 0.6 (the yield of one 80‑lb bag) to see how many bags to purchase. Use the values to get accurate quotes and avoid surprise over‑orders before you start the project.
Pro tips
- Add about 10% waste to the total volume to cover spillage and variations.
- Round the bag count up to the next whole bag; you can’t buy a fraction of a bag.
- Order ready‑mix in whole cubic yards to match supplier packaging.
- Double‑check that thickness is entered in inches; the calculator converts it to feet automatically.
Real-life examples
- A homeowner pouring a 4‑ft by 8‑ft patio slab 4 in thick.
- A contractor estimating material for a 10‑ft by 12‑ft garage floor 6 in thick.
- A landscaper calculating the mix needed for a raised garden bed 2 ft wide, 12 ft long, 3 in deep.
Case study
Mike needed a 5 × 10 ft patio 4 in thick. Using the calculator he saw the job required 1.33 cubic yards, which translated to 74 bags. He ordered 75 bags and avoided a costly second delivery, finishing the patio on schedule.