How many 80-lb bags of concrete are in a cubic yard?

It takes 45 eighty-pound bags to make one cubic yard. Each 80-lb bag yields about 0.60 cubic feet, and a cubic yard is 27 cubic feet, so 27 ÷ 0.60 = 45 bags.

How many 60-lb bags make a yard?

60 bags. A 60-lb bag yields 0.45 cubic feet, and 27 ÷ 0.45 = 60. A 40-lb bag yields 0.30 cubic feet, so it takes 90 of those to fill a yard.

Is it cheaper to buy bags or ready-mix?

Bags are more convenient for small pours. Past about one cubic yard, which is roughly 45 eighty-pound bags, ready-mix delivery is usually cheaper, faster, and more consistent. Mixing 45 bags by hand is a brutal day.

How Many Bags of Concrete Are in a Cubic Yard?

You are standing in the hardware-store aisle with a stack of concrete bags. How many do you need, and when should you call the ready-mix truck instead? This page gives the bag counts, the math, and the break-even point.

The short answer

A cubic yard of concrete is 27 cubic feet. Each bag yields a fixed volume, so divide 27 by the yield:

Bag size	Yield per bag	Bags per cubic yard
80 lb	0.60 ft³	45 bags
60 lb	0.45 ft³	60 bags
40 lb	0.30 ft³	90 bags

The Concrete Bag Calculator does this straight from your slab dimensions, so you never have to convert to yards.

Why bags are rated in cubic feet, not pounds

The weight on the bag is the dry mix. Once you add water, an 80-lb bag settles into about 0.60 cubic feet of finished concrete. Two bags of different weights can cost the same per cubic foot but very different amounts per bag, so compare on yield, not weight.

Worked example: a small pad

Say you are pouring a 6 ft × 6 ft shed pad, 4 inches thick:

Volume: (6 × 6 × 0.333) ÷ 27 = 0.44 cubic yards, or about 12 cubic feet
In 80-lb bags: 12 ÷ 0.60 = 20 bags
In 60-lb bags: 12 ÷ 0.45 = 27 bags

Twenty 80-lb bags is a doable weekend job with a wheelbarrow or a rented mixer. If the number had come back at 45 or more, price a ready-mix delivery instead. The Concrete Slab Calculator does this flat-slab math.

The bags-vs-ready-mix break-even

Under about one cubic yard, bags make sense. Over it, order the truck. Mixing 45 bags by hand means moving roughly 3,600 pounds of material twice, into the mixer and into the form. If you slow down, the first batch starts curing before the last one goes in, and the seam between them is a weak cold joint. Ready-mix arrives in one continuous pour.

Delivery has its own catch. Many suppliers charge a short-load fee below a full truck (about 10 yards) and set a minimum order. Bags work best from roughly 0.25 to 1 cubic yard, past a small repair but short of truck territory.

Don’t forget to order extra

Buy 5-10% more than the calculator says. Forms bulge slightly, the subgrade is never perfectly level, and you will spill some. Running one bag short mid-pour means a hardware-store run while your first batch sets. A leftover bag or two costs a few dollars, while a cold joint weakens the slab.

Quick reference: common pours

Project	Approx. volume	80-lb bags
Fence post hole (12in dia, 2ft deep)	~1.6 ft³	3 bags
3 × 3 ft landing, 4in	~3 ft³	5 bags
6 × 6 ft shed pad, 4in	~12 ft³	20 bags
10 × 10 ft patio, 4in	~33 ft³	56 bags → get ready-mix

The 10 × 10 patio is already past the bag threshold. Anything patio-sized or bigger is usually a ready-mix job.

Ready to estimate your pour?

Measure your length, width, and thickness, then run the numbers through the Concrete Bag Calculator for a bag count or the Concrete Calculator for cubic yards. Round up either way, and confirm the final quantity with your supplier before you buy.