How to use it
- Enter the length in feet.
- Enter the width in feet.
- Enter the thickness in inches and hit Calculate.
What it does – The Cement How Much Calculator turns the dimensions of your slab, patio, or footing into three useful numbers: cubic feet, cubic yards, and the number of 80‑lb bags of mix you’ll need. Why it matters – Ordering too little concrete means costly delays; ordering too much wastes money and space. Knowing the exact volume lets you budget accurately and schedule deliveries with confidence. How to read the results – Cubic feet is the raw volume of the space. Divide by 27 to see cubic yards, the unit most suppliers quote. Divide cubic feet by 0.6 to get the approximate bag count. Use these figures to place a precise order. Add a 5‑10% waste allowance for uneven subgrade, and round up to the nearest whole bag to avoid shortfalls.
Pro tips
- Add 5‑10% extra for waste and uneven subgrade
- Round up bag count to the next whole bag
- Order bags from a supplier that delivers to your site
- Double‑check thickness conversion from inches to feet
Real-life examples
- Estimating concrete for a new driveway slab
- Sizing a backyard patio before ordering material
- Calculating footing volume for a small shed foundation
Case study
John needed a 12 ft × 12 ft patio 4 in thick. Using the calculator he saw the job required 1.3 yd³ or 56 bags, ordered exactly that, and avoided a $200 over‑order.