Guides & tutorials that support the Concrete Bags Calculator.
Dry-pour concrete places dry bagged mix directly into a hole — no pre-mixing required. This guide covers the bag-count formula by square feet and depth, worked examples for fence posts and pads, a quick-reference table for 40/60/80 lb bags, and when the method is safe to use.
A practical comparison of common retail bag sizes across regions and how they affect counts.
Sizing concrete for small retaining walls using bag counts with safety buffers.
Diameter, depth, and spacing guidelines to figure out post-hole bag counts.
Rectangular footing math — length × width × height and waste buffers.
From 4-inch patios to garage floors — bag counts with examples.
40 vs 50 vs 60 vs 80 lb vs 20 kg — which bag size and mix is right for you?
What's actually blended inside a bag of pre-mix, how that ratio sets the cured PSI, and why an 80 lb bag covers less than you'd expect. Bag-specific — not nominal M-grade design.
Bags win under half a yard; ready-mix wins past one. A field guide to the crossover point, the labor it hides, water control, and what goes wrong on site.
Need instant results? Use the Concrete Bag Calculator.