How many bags of concrete make a cubic yard?
An 80 lb bag yields approximately 0.60 cubic feet. There are 27 cubic feet in a cubic yard, so you need roughly 45 bags of 80 lb concrete per cubic yard. For 60 lb bags (0.45 cubic feet yield), you need about 60 bags per yard. This calculator handles both bag sizes and shows your bag count alongside the cubic yard total.
What is the standard slab thickness for residential work in Canada?
4 inches (100 mm) is the standard thickness for residential driveways, patios, and garage floors in Canada. Sidewalks and footpaths use 3–4 inches. Slabs exposed to heavy vehicles or equipment typically require 5–6 inches. Always verify with your local building code and structural engineer for load-bearing applications.
How much extra concrete should I order?
Add 5–10% waste for standard rectangular pours. Use 10% for complex formwork, irregular shapes, or if your measurements may be imprecise. Running short mid-pour creates cold joints and structural problems — ordering a bit extra is far less expensive than a second truck or rejected slab.
When should I use bagged concrete versus ready-mix delivery?
Bagged concrete is practical for pours under 1–1.5 cubic yards. Above that, ready-mix truck delivery is more cost-effective and gives you a more consistent, better-mixed product without the manual labour of mixing bags. This calculator shows your volume so you can make that call before pricing the job.
How do I calculate concrete for a round slab or pad?
For a round pad, the formula is π × radius² × depth (all in feet) to get cubic feet, then divide by 27 for cubic yards. This calculator handles round slabs and columns directly — enter your diameter and depth and it does the conversion. Most estimating errors on round pads come from using diameter instead of radius in the formula.
