How to use it
- Enter length in feet
- Enter width in feet
- Enter thickness in inches
- Read cubic yards, cubic feet and bag count
What it does – You enter the length, width, and thickness of the slab. The tool instantly converts those dimensions to cubic feet, then to cubic yards (1 cubic yard = 27 cubic feet), and finally estimates how many 80‑lb bags are required using the standard 0.6 ft³ per bag.
Why it matters – Ordering too little concrete delays projects and costs extra labor; ordering too much wastes money and creates cleanup. Knowing the exact yardage lets you price the job accurately and communicate clear specs to suppliers.
How to read the results – Cubic feet is the raw volume of your pour. Divide by 27 to get cubic yards, the unit most suppliers quote. Multiply cubic feet by 1⁄0.6 (or divide cubic yards by 0.0222) to see the number of bags; round up to the nearest whole bag.
Pro tips
- Add 5‑10% extra for spillage and uneven subgrade
- Round up bag count; you can’t purchase a fraction of a bag
- Order bags in full pallets when possible to reduce delivery fees
- Double‑check thickness; a common mistake is entering inches as feet
Real-life examples
- Homeowner planning a 12 ft × 10 ft patio 4 in thick
- Contractor estimating concrete for a 30 ft × 20 ft garage floor 5 in thick
- Landscaper needing material for an 8 ft × 6 ft garden walkway 3 in thick
Case study
John needed a 15 ft × 12 ft slab 4 in thick for his workshop. Using the calculator, he saw he required 2.2 cubic yards, which translated to 7 bags. He ordered 8 bags, avoided a costly second delivery, and finished on schedule.