Srm Concrete Calculator

Instantly calculate the concrete you need—cubic yards, bags, and cubic feet—for any slab size, free and online.

  • Free
  • No sign-up
  • Instant results

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How to use it

  1. Enter length in feet.
  2. Enter width in feet.
  3. Enter thickness in inches.
  4. Click Calculate to see cubic yards, bags, and cubic feet.

What it does – The Srm Concrete Calculator turns the three dimensions you input (length ft, width ft, thickness in) into three useful measures: total cubic feet, cubic yards, and the number of 80‑lb bags required. Why it matters – Knowing cubic yards helps you order the right amount of ready‑mix, while bag count is essential for DIY pours. How to read the results – Cubic feet is the raw volume; divide by 27 to get cubic yards. Multiply cubic feet by 1⁄0.6 (or divide by 0.6) to see how many bags you’ll need, rounding up to avoid shortfalls. The calculator updates instantly, so you can experiment with different slab sizes before you call a supplier. You can also save the numbers for budgeting or share them with your contractor. The tool works on any device, no download required.

Pro tips

  • Add a 10% waste allowance to the bag total.
  • Round up the bag count to the next whole bag.
  • Order a little extra if you’re near a delivery deadline.
  • Double‑check thickness conversion (inches to feet) before entering.

Real-life examples

  • A homeowner pouring a 4‑in concrete patio.
  • A contractor estimating material for a 6‑in garage floor.
  • A landscaper sizing a decorative stepping‑stone path.

Case study

Mike needed a 10 × 12 ft patio 4 in thick. Using the calculator he saw the job required 1.23 cubic yards, about 56 bags. He ordered 60 bags, avoided a short‑run, and completed the pour on schedule.

Frequently asked questions

How do I convert thickness in inches to feet?
Divide the inches by 12; the calculator does this automatically when you enter the thickness.
Why does the calculator show both cubic yards and bags?
Cubic yards are used for ready‑mix orders, while bags are needed for DIY mix deliveries.
Do I need to add waste to the bag count?
Yes, add about 10% extra to cover spillage and uneven sub‑grade.
Can I use the results for ordering ready‑mix concrete?
Absolutely—use the cubic yards figure to tell the supplier how much concrete to deliver.
Is the bag yield of 0.6 cubic feet accurate for all mixes?
0.6 cf per 80‑lb bag is a standard estimate; actual yield may vary slightly by brand.