Quikrete Cubic Yards Per Bag: Exact Coverage

One 80-pound bag of Quikrete concrete mix yields approximately 0.6 cubic feet, which equals about 0.022 cubic yards. To make one cubic yard, you need roughly 45 bags of the 80-pound size. This article explains the math, compares bag sizes, and helps you estimate how many bags your project needs.

Formula

The volume per bag depends on its weight. Quikrete’s standard mixes (like Concrete Mix, Sand Mix, or All-Purpose Gravel) all yield about 0.6 cubic feet per 80-pound bag, 0.45 cubic feet per 60-pound bag, and 0.375 cubic feet per 40-pound bag. The general formula is:

Volume (ft³) = Bag weight (lb) ÷ 133.33

Volume (yd³) = Volume (ft³) ÷ 27

Where 133.33 is the approximate weight of one cubic foot of mixed Quikrete (about 133–135 lb). The calculator above uses this to convert any number of bags and bag size into total cubic feet, cubic yards, and coverage area at a 4-inch slab depth.

Worked Example

Using the default values: 45 bags × 80 lb each.

1. Total weight = 45 × 80 = 3,600 lb
2. Total volume in cubic feet = 3,600 ÷ 133.33 = 27.0 ft³
3. Total volume in cubic yards = 27.0 ÷ 27 = 1.00 yd³
4. Coverage at 4″ deep: 27 ft³ ÷ 0.333 ft = 81 ft²

So 45 bags of 80 lb Quikrete make exactly 1 cubic yard, covering 81 square feet at 4 inches thick.

Why Bag Size Matters

Quikrete sells several bag weights, and the yield changes proportionally. The most common sizes are:

• 40 lb bag – yields about 0.30 ft³ (0.011 yd³). You’d need about 90 bags per cubic yard.
• 50 lb bag – yields about 0.375 ft³ (0.014 yd³). About 72 bags per cubic yard.
• 60 lb bag – yields about 0.45 ft³ (0.017 yd³). About 60 bags per cubic yard.
• 80 lb bag – yields about 0.60 ft³ (0.022 yd³). About 45 bags per cubic yard.

These numbers apply to standard Quikrete concrete, sand mix, and mortar mixes. Specialty products (like fast-setting or high-strength) may have slightly different yields because of density differences, but the difference is usually small.

How to Estimate Bags for Your Project

First, calculate the volume of concrete you need in cubic feet or yards. For a slab, use:

Volume = Length (ft) × Width (ft) × Thickness (ft)

Then divide by the per-bag yield. For example, a 10 ft × 10 ft slab at 4 inches thick:

1. Thickness = 4 in ÷ 12 = 0.333 ft
2. Volume = 10 × 10 × 0.333 = 33.3 ft³
3. Using 80 lb bags: 33.3 ÷ 0.6 = 55.5 → round up to 56 bags

Always round up. It’s better to have a partial bag left over than to run short mid-pour.

Common Mistakes and Misconceptions

A frequent error is confusing cubic feet with cubic yards. One cubic yard is 27 cubic feet, not 3. Another mistake is assuming all 80 lb bags yield the same volume – they do for standard mixes, but fast-setting or high-early-strength mixes can be denser and yield slightly less. Also, the yield is for the mixed, hardened concrete, not the dry powder. When you add water, the volume shrinks slightly, so the dry bag volume is not the final volume. Finally, don’t forget waste: for small jobs, add 10% extra; for complex forms or rebar, add 15–20%.

Bagged vs. Ready-Mix Concrete

For small projects (less than about 1 cubic yard), bagged concrete is convenient and cost-effective because you can mix only what you need. For larger pours, ready-mix concrete delivered by truck is usually cheaper per cubic yard and saves labor. A typical ready-mix truck carries 8–10 cubic yards. If your project needs more than 1–2 cubic yards, compare prices: bagged concrete often costs 3–4 times more per cubic yard than ready-mix, but you avoid delivery minimums and scheduling.

Cost and Practical Considerations

Bagged concrete prices vary by region and store, but a typical 80 lb bag costs $4–$6. At 45 bags per cubic yard, that’s $180–$270 per cubic yard. Ready-mix might cost $120–$150 per cubic yard plus a delivery fee. For a single small slab, the convenience of bags outweighs the cost. For a driveway or large patio, ready-mix is almost always the better choice. Also consider mixing effort: each 80 lb bag requires about 3–4 gallons of water and significant mixing time. A 1-cubic-yard pour (45 bags) is a full day of work for two people.

Safety and Mixing Tips

Concrete dust is harmful if inhaled, so wear a dust mask and safety glasses. Wet concrete is caustic – avoid skin contact and wash any spills immediately. Mix on a hard, clean surface or in a wheelbarrow. Add water gradually, mixing thoroughly to a uniform consistency. For structural projects (like footings or load-bearing walls), check local building codes and consider consulting an engineer. Never pour concrete in freezing temperatures or during heavy rain. Always follow the mixing instructions on the bag for water amounts – too much water weakens the concrete.

Frequently Asked Questions

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

Exactly 45 bags. Each 80 lb bag yields 0.6 cubic feet, and 27 cubic feet divided by 0.6 equals 45.

How much area does an 80 lb bag cover at 4 inches thick?

An 80 lb bag covers about 1.8 square feet at 4 inches deep. That’s 0.6 ft³ divided by 0.333 ft.

Can I mix a whole bag at once?

Yes, but it’s heavy. An 80 lb bag of dry mix weighs 80 lb, and after adding water it weighs about 90 lb. Mixing in a wheelbarrow is doable, but for larger batches consider renting a mixer.

Does Quikrete yield differ between mix types?

Standard mixes (concrete, sand mix, mortar) all yield about 0.6 ft³ per 80 lb bag. Fast-setting and high-strength mixes may be denser, so check the bag label – they often yield 0.5–0.55 ft³ per 80 lb bag.

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

For less than 1 cubic yard, bags are usually cheaper because ready-mix has delivery minimums. For more than 1–2 cubic yards, ready-mix is typically 30–50% cheaper per cubic yard.

How much water do I add to an 80 lb bag?

About 3–4 quarts (3–4 liters) of water per 80 lb bag, but always check the bag instructions. Add water gradually and mix to a workable consistency – too much water weakens the concrete.

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in bags | Number of bags | bags | 45 | 1
in size | Bag size | lb | 80 | 1
out vol_ft3 | Total volume | ft³ | bags * size / 133.33 | 1
out vol_yd3 | Total volume | yd³ | bags * size / 3600 | 2
out area_4in | Coverage at 4" deep | ft² | (bags * size / 133.33) / 0.333 | 0