Formula used
Cubic yards = [length × width × (thickness ÷ 12) ÷ 27] × (1 + waste ÷ 100)
Worked concrete footing example
Concrete Footing Calculator example: 20.1 ft × 1.5 ft × 8 in ÷ 12 ÷ 27 × 1.1 = 0.82 yd³. The same volume is about 38 80-lb premixed-concrete bags or 50 60-lb bags using the calculator's bag-yield constants.
From calculated volume to an order
Round the volume according to the ready-mix supplier's ordering increment and keep footing concrete separate from stem-wall or pier quantities.
Where a concrete takeoff can drift
Excavation overbreak, stepped footings, keyways, grade changes, and soil falling into the trench all affect placed volume.
Questions specific to this calculation
Which finished dimensions define the concrete footing placement?
Treat the inputs as one continuous rectangular footing: total centerline length, formed width, and concrete thickness. Calculate isolated pads separately.