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60 and 80 lb Concrete Bag Calculator

Calculate 60 and 80 lb Concrete Bag
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Definition

What is 60 and 80 lb Concrete Bag Calculator?

The 60 and 80 lb concrete bag calculator converts project volume into the exact number of pre-mixed concrete bags needed in both sizes. Pre-mixed concrete bags (such as Quikrete and Sakrete) contain cement, sand, and gravel in the correct ratio — just add water.

The two most popular bag sizes for DIY concrete projects are:

  • 80 lb bag: Yields 0.6 ft³ (0.017 m³) of mixed concrete. Best value per cubic foot. ~$5.50–$7.50 per bag.
  • 60 lb bag: Yields 0.45 ft³ (0.013 m³) of mixed concrete. Easier to lift and carry. ~$4.50–$6.00 per bag.

An 80 lb bag provides 33% more concrete than a 60 lb bag but weighs 33% more. For small projects (post holes, minor repairs), 60 lb bags are easier to handle. For larger projects (slabs, footings), 80 lb bags are more cost-effective per cubic foot.

Formula

60 and 80 lb Concrete Bag Calculator Formula

Number of bags = Total volume (ft³) ÷ Yield per bag (ft³)

Bag SizeYield per BagBags per Cubic YardBags per Cubic Meter
80 lb bag0.60 ft³45 bags59 bags
60 lb bag0.45 ft³60 bags79 bags
50 lb bag0.375 ft³72 bags95 bags
40 lb bag0.30 ft³90 bags118 bags

Example for 2 cubic yards:

  1. Convert to ft³: 2 × 27 = 54 ft³
  2. 80 lb bags: 54 ÷ 0.60 = 90 bags
  3. 60 lb bags: 54 ÷ 0.45 = 120 bags
Examples

Worked Examples

1 Cubic Yard

27 ft³ needs 45 bags of 80 lb or 60 bags of 60 lb. Weight: 3,600 lbs (80 lb) vs 3,600 lbs (60 lb).

0.5 Cubic Yards

13.5 ft³ needs 23 bags of 80 lb or 30 bags of 60 lb. Good size for small slab or several post holes.

3 Cubic Yards

81 ft³ needs 135 bags of 80 lb or 180 bags of 60 lb. At this volume, ready-mix delivery is recommended.

10 Cubic Feet

Needs 17 bags of 80 lb or 23 bags of 60 lb. Typical for a small pad or a few post holes.

FAQ

Frequently Asked Questions

Answers to common questions about the 60 and 80 lb concrete bag calculator.

45 bags of 80 lb concrete make 1 cubic yard. Each 80 lb bag yields 0.6 ft³ of mixed concrete, and 1 cubic yard = 27 ft³. So 27 ÷ 0.6 = 45 bags.

60 bags of 60 lb concrete make 1 cubic yard. Each 60 lb bag yields 0.45 ft³ of mixed concrete. So 27 ÷ 0.45 = 60 bags.

80 lb bags are typically 15–20% cheaper per cubic foot of concrete. An 80 lb bag costs ~$6.50 and yields 0.6 ft³ ($10.83/ft³). A 60 lb bag costs ~$5.50 and yields 0.45 ft³ ($12.22/ft³). For any project over 5 bags, 80 lb bags save money.

Use 60 lb bags when lifting 80 lbs is difficult — for one-person projects, carrying bags upstairs or across uneven ground, or when the worker has back or joint limitations. The lighter weight makes mixing by hand easier. The per-bag cost difference is small on small projects.

Add approximately 3 quarts (2.8 liters) of water per 80 lb bag. For a 60 lb bag, add about 2.25 quarts (2.1 liters). Start with less water and add gradually — the mix should be workable but not soupy. Too much water reduces strength.

Switch to ready-mix delivery for projects over 1 cubic yard (45 bags). Ready-mix costs $125–$165 per cubic yard delivered. At $6.50 per bag, 45 bags cost $292.50 — more than double the ready-mix price. Plus, mixing 45 bags by hand takes hours versus minutes for a ready-mix pour.