Question 1

How many bags of concrete do I need?

Accepted Answer

It depends on your project volume and bag size. Calculate your volume in cubic feet (length × width × depth in feet), then divide by the bag yield: 0.30 cu ft for 40 lb, 0.45 cu ft for 60 lb, or 0.60 cu ft for 80 lb. Always round up to the next whole bag.

Question 2

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

Accepted Answer

There are approximately 45 bags of 80 lb concrete in one cubic yard. Each 80 lb bag yields about 0.60 cubic feet, and there are 27 cubic feet in a cubic yard (27 ÷ 0.60 = 45).

Question 3

How many 60 lb bags of concrete are in a cubic yard?

Accepted Answer

Approximately 60 bags of 60 lb concrete make one cubic yard. Each 60 lb bag yields about 0.45 cubic feet (27 ÷ 0.45 = 60).

Question 4

How much does a bag of concrete cover?

Accepted Answer

An 80 lb bag covers about 0.60 cubic feet, which is roughly a 2 ft × 2 ft area at 2 inches thick, or a 1.5 ft × 1.5 ft area at 4 inches thick. A 60 lb bag covers about 0.45 cubic feet.

Question 5

Which is better — 60 lb or 80 lb concrete bags?

Accepted Answer

80 lb bags offer the best value per cubic foot and require fewer bags. 60 lb bags are easier to carry and mix. Choose 80 lb for larger projects to minimize bag count, and 60 lb when weight handling is a concern.

Question 6

How many bags of concrete for a fence post?

Accepted Answer

A typical fence post hole (8 inch diameter, 24 inches deep) needs about 1 bag of 80 lb concrete or 2 bags of 60 lb. For 10 fence posts, plan on 10–12 bags of 80 lb with a waste factor.

Question 7

How many bags of concrete for a 10×10 slab?

Accepted Answer

A 10×10 slab at 4 inches thick requires about 33.3 cubic feet of concrete. That equals approximately 56 bags of 80 lb, 74 bags of 60 lb, or 111 bags of 40 lb. At this volume, ready-mix delivery is usually more practical.

Question 8

Is it cheaper to buy bags or order ready-mix?

Accepted Answer

Bags are cheaper for projects under about 0.75–1 cubic yard. Above that, ready-mix is more cost-effective. Bagged concrete costs $180–$250 per cubic yard equivalent, while ready-mix costs $125–$175 per yard plus delivery.

Question 9

How many bags of concrete fit in a pickup truck?

Accepted Answer

A standard pickup truck with a 1,500 lb bed capacity can carry about 18 bags of 80 lb concrete or 25 bags of 60 lb per trip. Plan your trips accordingly for larger projects.

Question 10

How long does an unopened bag of concrete last?

Accepted Answer

Unopened bags of concrete can last 3–6 months when stored in a dry location off the ground. Moisture causes premature hardening. Once opened, use the bag within 24 hours.

Bag Size	Yield (cu ft)	Yield (cu yd)	Bags / Yard
40 lb	0.30	0.011	90
50 lb	0.375	0.014	72
60 lb	0.45	0.017	60
80 lb	0.60	0.022	45

Volume	80 lb Bags	Bag Cost*	Ready-Mix**	Winner
0.25 yd³	12	$66–$96	$150 + del.	Bags
0.50 yd³	23	$127–$184	$175 + del.	Bags
1.0 yd³	45	$248–$360	$150–$175	Ready-Mix
2.0 yd³	90	$495–$720	$300–$350	Ready-Mix

Concrete Bags Calculator

How Many Bags of Concrete Do I Need?

Concrete Bag Yield by Size

How to Calculate Bags Needed

Bags vs. Ready-Mix — When to Switch

Concrete Bags Calculator — Examples

Bags for 10 Fence Post Holes

Bags for a Small Patio (8×8)

Bags for 4 Deck Post Footings

Why Use MaterialCalc's Bags Calculator?

Related Concrete Calculators

Concrete Bags Calculator — Frequently Asked Questions