How much concrete for a 16x20 patio?

A 16x20 patio at 4in depth requires about 218 bags of 80lb premix or 4.9 cu yd ready-mix. At this volume, ready-mix delivery is almost always the better choice. Calculator pre-filled below.

Length (ft)

Width (ft)

Depth (inches)

Waste factor (%)

Material Totals

Concrete volume (with waste) 4.35 cu yd

80lb premix bags needed 196 bags

60lb premix bags needed 261 bags

Raw volume (no waste) 3.95 cu yd

1 cu yd = 27 cu ft. One 80lb bag covers ~0.6 cu ft; one 60lb bag ~0.45 cu ft. For pours over ~1 cu yd, ready-mix delivery is usually more economical.

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Project 16ft x 20ft x 4in

Concrete (80lb bags) (recommended) 196 bags

Concrete (60lb bags) (alternative) 261 bags

Or: ready-mix concrete 4.35 cu yd

Generated by BuildTotals.com | 6/13/2026 | buildtotals.com/tools/concrete-calculator

Estimates include 10% waste factor. Confirm with your supplier before purchasing.

At nearly 5 cubic yards, this project is well beyond DIY bag mixing. Call 2-3 local ready-mix suppliers for quotes. A standard truck carries 8-10 yards; you will pay a short-load fee but it is still faster and cheaper than bags at this volume.

Adjust dimensions in the full calculator