How Many 80 lb Bags for 20 Cubic Feet of Concrete?
How many 80 lb bags will you need to fill 20 cubic feet of space? For this volume, you'll require 34 bags of concrete.
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Bag Count at a Glance
Bag yield used: 0.6 ft³ per bag. Bag yield guide
Project Notes
Check the bag yield on the label and round your count up before buying so a small shortfall does not turn into an extra store run.
Using the wrong yield can lead to underestimating the number of bags needed for your project.
Keep each batch as consistent as possible and avoid long pauses between mixes so the surface and finish stay more uniform while the concrete cures.
On-Site Pointers for 80 lb Bags
This volume is ideal for medium-sized DIY projects like patios or shed slabs, providing a solid foundation for outdoor spaces. Perfect for those looking to enhance their property with durable surfaces.
You’ll need to manage 34 bags, totaling 2,720 pounds. Plan for multiple trips or enlist help to ensure safe handling and easy transport to your project site.
For projects of this scale, bagged concrete is convenient and manageable. However, consider ready-mix for larger pours to save time and reduce labor.
Worked Example for 20 cubic feet with 80 lb Bags
Step-by-step calculation for this exact volume and bag size:
- Volume in cubic feet: 19.98 ft³ (= 0.740 yd³ × 27)
- Bag yield: 0.6 ft³ per 80 lb bag
- Base bag count: 19.98 ÷ 0.6 = 34 bags (rounded up)
- With 10% waste: 34 × 1.10 = 37 bags
- Total weight: 34 × 80 lb = 2,720 lb
Bag Counts by Waste Buffer for 20 cubic feet
Pick a buffer based on site conditions: clean forms and accurate volume can run leaner; rough subgrade or hard-to-reach pours need more cushion.
| Buffer | 80 lb bags | Total weight |
|---|---|---|
| No buffer tight pour | 34 | 2,720 lb |
| +5% typical DIY | 35 | 2,800 lb |
| +10% recommended | 37 | 2,960 lb |
| +15% rough conditions | 40 | 3,200 lb |
How to Use This Estimate
Confirm volume
Start with 20 cubic feet and verify whether your total is in cubic feet or cubic yards.
Check bag yield
This page assumes 0.6 ft³ per 80 lb bag.
Add waste
Use the 5% or 10% buffer if you expect spillage, uneven forms, or small measurement errors.
Planning Notes
When bagged concrete makes sense: smaller pours, simple DIY jobs, and areas where a ready-mix truck is inconvenient.
When to compare ready-mix: once bag counts become very high, delivery may save labor and time. See our concrete cost per yard guide.
For more tools and conversions, visit the Concrete Calculator hub.
Bag Concrete FAQs for 20 cubic feet
What does bag yield mean and how can I check it?
Bag yield refers to the volume of concrete you can expect from a single bag, which can be found on the label of each bag.
Should I round up when ordering bags?
Yes, it’s wise to round up to account for any potential waste or miscalculations during your project.
When is bagged concrete a good choice for my project?
Bagged concrete is suitable for small pours like patios, walkways, and shed slabs where convenience and portability are key.
In what situations might ready-mix concrete be a better option?
Ready-mix might be preferable for larger projects where extensive volume is needed quickly or for more complex mixes.
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