Example Tool
Bagged Concrete Mix product recommendation placeholder
Concrete Bag Calculator
Work out how many bags of premixed concrete your project needs — from project dimensions, a known volume or an area and thickness. Compare 40, 50, 60, 80 and 90 lb bags, custom international bag yields, packaged weight and cost.
- Free
- No signup
- Metric & Imperial
Bag estimate
How many bags do you need?
Enter your project dimensions, a known volume or an area and thickness, choose a bag size and select Calculate to see bag quantities, packaged weight and optional cost.
How Many Bags of Concrete Do I Need?
The number of bags depends on three things: the concrete volume your project needs, the yield of the bag you buy, and the waste allowance you choose.
Bags Needed = Required Concrete Volume ÷ Yield Per Bag
Always round up to the next whole bag, because partial bags normally cannot be purchased.
How to Use the Concrete Bag Calculator
- 1Choose how you want to enter your project.
- 2Enter the project dimensions, area or known volume.
- 3Choose your bag size, or compare all sizes.
- 4Select a waste allowance.
- 5Optionally enter the price per bag, then select Calculate.
Then compare the total number of bags, the packaged weight and the estimated cost for each bag size.
How the Calculation Works
The calculator converts your measurements to a single internal volume, applies your waste allowance and divides by the yield of the bag you selected.
Project requires 22 ft³ including waste
80 lb bag yield ≈ 0.60 ft³
22 ÷ 0.60 = 36.67
Round up → 37 bags
Concrete Bag Yield Reference
| Bag size | Approximate yield | Approximate liters |
|---|---|---|
| 40 lb | 0.3 ft³ | 8.5 L |
| 50 lb | 0.375 ft³ | 10.6 L |
| 60 lb | 0.45 ft³ | 12.7 L |
| 80 lb | 0.6 ft³ | 17.0 L |
| 90 lb | 0.675 ft³ | 19.1 L |
These are approximate reference yields. Actual yield varies by product. Check the manufacturer's packaging or technical data before purchasing.
Understanding Concrete Bag Yield
Bag weight and yield are not the same thing. An 80 lb bag does not produce 80 lb of finished concrete measured as a volume — the number on the bag is the dry weight of the mix inside it.
Yield is the approximate volume of mixed concrete the bag produces once water has been added and the mix has been prepared properly. Because formulations differ, yield varies between products, so verify the product-specific yield before you buy.
Comparing Concrete Bag Sizes
Larger bags generally mean fewer bags to buy, carry and mix, but each individual bag is heavier. Smaller bags mean more individual bags, with less weight per bag.
There is no single best bag size. Availability, handling, mixing method and price vary by store and product, so compare the totals for each size and choose what suits your project.
Tips Before Buying
- Measure the project in several places — surfaces are rarely perfectly even.
- Confirm the yield printed on the bag you plan to buy before ordering.
- Allow for uneven surfaces and spillage with a waste allowance you are comfortable with.
- Check how many bags you can transport and handle in one trip.
- Compare bagged concrete with ready-mix delivery for larger pours.
Disclaimer: BuildCalcWorks provides planning estimates only and does not provide structural engineering advice. Actual quantities vary with site conditions, mixing, product yield and measurement accuracy. Verify quantities before purchasing materials. Read full Disclaimer.
Related Calculators
Frequently Asked Questions
Tools & Materials for Your Project
Helpful products and materials related to this calculation.
Disclosure: BuildCalcWorks may earn a commission from qualifying purchases made through links on this page, at no additional cost to you.
Example Tool
Concrete Mixing Tools product recommendation placeholder
Example Tool
Mixing Tubs product recommendation placeholder
Example Tool
Concrete Mixers product recommendation placeholder
Example Tool
Wheelbarrows product recommendation placeholder
Example Tool
Concrete Finishing Tools product recommendation placeholder
Example Tool
Safety Equipment product recommendation placeholder
Related Guides
Flooring
How to Calculate Square Footage for Flooring
Learn how to calculate square footage for flooring, measure rooms correctly, account for irregular areas and add waste before ordering flooring materials.
Read guideFlooring
How Much Extra Flooring Should You Buy?
Learn how much extra flooring to buy for cuts and waste, when to use 5%, 10% or 15%, and how to calculate boxes for your flooring project.
Read guide