Concrete Calculators
Figure out exactly how many bags — or how many cubic yards — a pour needs, before you're standing at the register guessing.
Patios, walkways, shed floors and driveways. Enter length, width and thickness for bags or cubic yards.
The strip footing under a wall or slab edge. Enter run length, width and thickness.
Round form tubes for deck and post footings. Enter diameter, height and tube count.
Bags per post hole, subtracting the post's own volume from the hole. Enter post count and hole size.
Foundation and stem walls. Enter wall length, height and thickness.
Landscape edging or driveway curb. Enter run length, width and height.
Outdoor concrete stairs. Enter width, rise, run and number of steps.
How much a poured slab weighs, in pounds and tons.
How much concrete do I need?
Every calculator here starts from the same volume math: length × width (or the shape's area) × thickness, converted to cubic feet, then to cubic yards or bags. The difference between them is the shape — a slab or poured wall is a flat rectangle, a footing or curb is a long narrow strip, a sonotube is a cylinder, steps are a stack of rectangles, and a fence post hole is a cylinder with the post's own volume subtracted out.
As a rough rule, bags make sense up to about 1 to 2 cubic yards. Past that, a ready-mix delivery is usually faster and cheaper — see concrete cost per yard to compare.