Enter slab, footing, or column dimensions to find how many bags you need.
Formula: Volume (cu ft) = Length × Width × (Depth ÷ 12). Divide by the volume per bag, then add your waste factor. For slabs over 1 cubic yard, ordering ready-mix concrete is usually cheaper and faster. A standard 4" slab needs about 0.31 bags per square foot (80 lb bags).
Calculates gallons needed for walls. Automatically deducts doors and windows.
Enter actual (not nominal) dimensions. Board feet = (T × W × L) ÷ 12.
Find the correct copper wire gauge for your circuit based on amperage, run length, and allowable voltage drop.
Calculate water flow rate and velocity in a pipe (Hazen-Williams method). For water at ~60°F.
Calculate squares of roofing and number of shingle bundles needed for any roof pitch.
Calculate tiles needed for floors or walls. Accounts for grout joints and diagonal layouts.
Build a quick estimate with labor, materials, overhead, and markup.