How to use it
- Enter the wall's length in feet.
- Enter the wall's width (thickness) in feet.
- Enter the wall's thickness in inches.
- Click Calculate to see cubic yards, cubic feet, and bag count.
This calculator tells you exactly how much concrete you need for a wall. You enter three measurements: length, width, and thickness. It returns the volume in cubic feet and cubic yards, plus the number of 80-lb bags required. That last number matters because ready-mix isn't practical for small walls—you'll be mixing bags. The calculator uses a standard yield: one 80-lb bag covers about 0.6 cubic feet. So if your wall is 10 feet long, 1 foot wide, and 1 foot thick, that's 10 cubic feet. Divide by 0.6 and you'll need about 17 bags. The result helps you budget, avoid over-ordering, and plan the work. You'll know whether to rent a mixer or hand-mix. You'll also see cubic yards, which is useful if you decide to order ready-mix for a large wall. No guesswork, no running out mid-pour, no piles of extra bags cluttering your site.
Pro tips
- Add 10% extra for waste and spillage—round up to the nearest bag.
- For odd thicknesses, convert inches to feet first (e.g., 6 in = 0.5 ft) for accurate volume.
- Order bags in full pallets if possible—many suppliers require a minimum and you'll save on damage.
- Don't use the cubic yards number for bag ordering—use bags, or you'll misjudge by a factor of 27.
Real-life examples
- Pouring a small retaining wall in a residential backyard.
- Building a concrete garden wall or planter border.
- Estimating concrete for a foundation stem wall on a DIY shed.
Case study
Mark needed a 12-ft long, 1-ft wide, 1-ft tall wall. He used the calculator, saw 12 cu ft, and divided by 0.6 to get 20 bags. He bought 22 with waste, finished in one day, and had no leftover concrete.