Answer · Concrete

Concrete bag yield: cubic feet per bag (every size)

Updated April 26, 2026

Quick answer

Standard pre-mixed concrete bag yields: 40 lb = 0.30 ft³, 50 lb fast-set = 0.375 ft³, 60 lb = 0.45 ft³, and 80 lb = 0.60 ft³. Multiply your project volume in cubic feet by the inverse of these numbers to get bag count, then add a 10% waste factor and round up.

Open the concrete calculator →

Bag yield reference chart

Cubic-foot yield by bag size and product (Quikrete spec, others similar)

Bag size	Yield (ft³)	Yield (yd³)	Bags per yd³
40 lb	0.30 ft³	0.0111 yd³	90 bags
50 lb fast-setting	0.375 ft³	0.0139 yd³	72 bags
60 lb	0.45 ft³	0.0167 yd³	60 bags
80 lb	0.60 ft³	0.0222 yd³	45 bags
90 lb high-strength	0.675 ft³	0.025 yd³	40 bags

Yields assume Quikrete pre-mix specs. Sakrete, Maximizer, and Type S masonry mixes vary by ±5%. Always check the side panel of the bag for the actual yield rating.

Why the numbers aren't linear

An 80 lb bag yields 0.60 ft³, exactly 2× a 40 lb bag (0.30 ft³). But a 60 lb bag yields 0.45 ft³, which is 1.5× the 40 lb. The relationship scales with weight because the dry mix density is constant. Where it breaks is across product lines: fast-setting concrete has slightly more aggregate per pound, so a 50 lb fast-set bag yields 0.375 ft³ instead of the 0.375 you'd predict from a standard mix. Always use the rating on the bag.

Formula

Bag count from volume

bags = ceil( cubic_feet × (1 + waste%) ÷ yield_per_bag )

Example: 33.3 ft³ slab + 10% waste, 80 lb bags
= ceil( 33.3 × 1.10 ÷ 0.60 )
= ceil( 61.05 )
= 62 bags

Volume × 1.10 covers spillage, mixing loss, and the few bags that inevitably break or get wet on the truck ride home. Some sites recommend 5% waste for indoor/controlled pours; we say 10% as a safe default for any DIY project.

Worked example

Sidewalk: 30 ft × 3 ft × 4 in

Standard residential walkway. Compare 40, 60, and 80 lb bag counts.

1. Volume = 30 × 3 × (4/12)30 ft³
2. + 10% waste33 ft³
3. 40 lb: 33 / 0.30110 bags
4. 60 lb: 33 / 0.4574 bags
5. 80 lb: 33 / 0.6055 bags

→ 55 × 80 lb is the cheapest per-pound option, and the fewest trips with a hand truck.

How to convert cubic yards to bags

Ready-mix is sold in cubic yards. To convert your "I need 1.5 yd³" order into bag count, multiply by 27 to get cubic feet, then divide by bag yield. Or use the shortcut: 1 yard = 45 bags of 80 lb, 60 bags of 60 lb, or 90 bags of 40 lb. At about 1 yard, ready-mix from a truck is usually cheaper than bags once you factor in mixing time.

Quick yard-to-bag conversion

Cubic yards	80 lb bags	60 lb bags	40 lb bags
0.25 yd³	12	15	23
0.50 yd³	23	30	45
0.75 yd³	34	45	68
1.0 yd³	45	60	90
1.5 yd³	68	90	135
2.0 yd³	90	120	180

Brand differences worth knowing

Quikrete standard pre-mix: 0.60 ft³ for 80 lb. Most common reference.
Quikrete Maximizer: rated for higher strength but same yield per pound, 0.60 ft³ for 80 lb.
Sakrete High-Strength 5000: 0.60 ft³ for 80 lb.
Quikrete Fast-Setting (red bag): 0.375 ft³ for 50 lb , sets in 20–40 minutes.
Type S mortar mix: ~0.50 ft³ for 80 lb (different aggregate ratio, don't substitute for slab pours).

Common mistakes (and how to avoid them)

✗ Using mortar mix yield (0.50 ft³) for slab calculations.

Fix: Mortar and concrete are different products. Mortar has finer aggregate and a lower yield per pound. Use only concrete pre-mix bags for slabs and footings.

✗ Calculating bags from cubic inches instead of cubic feet.

Fix: Always convert dimensions to feet first. 1 cubic foot = 1,728 cubic inches, easy to misplace zeros and order 10× too many bags.

✗ Forgetting that the bag is dry weight, not finished volume.

Fix: An 80 lb bag of dry mix becomes 0.60 ft³ of finished concrete after mixing with water. The bag weight ≠ finished weight (water adds ~10 lb to an 80 lb bag).

✗ Skipping the 10% waste factor on small jobs.

Fix: On a 5-bag job, 10% = 0.5 bags. Always round up. The cost of one extra bag is $5, the cost of stopping mid-pour is your weekend.

→ Run bag count for any project size

Frequently asked questions

How many cubic feet in an 80 lb bag of concrete?

0.60 cubic feet of mixed concrete per 80 lb bag of standard Quikrete pre-mix. Same yield for Sakrete and most other major brands.

How many cubic feet in a 60 lb bag of concrete?

0.45 cubic feet per 60 lb bag, exactly 75% of an 80 lb bag's yield, matching the weight ratio.

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

45 bags of 80 lb to make one cubic yard (27 ft³ ÷ 0.60 ft³). Or 60 bags of 60 lb, or 90 bags of 40 lb.

Is fast-setting concrete the same yield as regular?

Almost, 50 lb fast-set yields 0.375 ft³ vs 50 lb regular at 0.375 ft³ as well. The difference is set time (20–40 min for fast-set), not volume.

How accurate are these yield numbers?

Within ±5% for any major brand. The exact yield depends on aggregate density and how much water you mix in. Always check the bag label for the manufacturer's spec.

Can I substitute mortar mix for concrete on a slab?

No, mortar has finer aggregate, lower yield (~0.50 ft³ per 80 lb), and lower compressive strength. Use only concrete pre-mix for slabs, footings, and driveways.

Concrete bag yield: cubic feet per bag (every size)

Bag yield reference chart

Why the numbers aren't linear

Bag count from volume

Sidewalk: 30 ft × 3 ft × 4 in

How to convert cubic yards to bags

Brand differences worth knowing

Common mistakes (and how to avoid them)

Frequently asked questions

Related answers & calculators

Concrete calculator

10×10 slab bag count

Ready-mix vs bagged cost

Slab thickness guide

Gravel base under the slab