Calculate how many bags of concrete you need for a slab or rectangular pour from length, width, thickness, waste and the actual yield printed on the concrete bag.
How many bags of concrete do I need?
Enter the pour length, width and thickness to calculate concrete volume, then enter the finished concrete yield stated on your specific bag. Calcavera divides the required volume by the yield and rounds up to a whole number of bags.
Use the bag yield, not only bag weight
A 40 lb, 50 lb, 60 lb, 80 lb or metric bag size does not by itself guarantee one universal finished volume. Product formulations differ. Use the yield shown on the package or manufacturer data sheet rather than assuming a fixed value for every brand.
Waste and real pours
The theoretical rectangular volume can be increased with an allowance for site variation, spillage and measurement uncertainty. The appropriate allowance depends on the project; it is not a substitute for measuring known deeper sections separately.