Bag Concrete Calculator
Bag concrete calculator works out Volume and Volume including waste allowance from Element being poured, How many identical elements and Length. The default figures on this page give volume of 1.2346 yd3; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
4 steps
- slab: 10 ft x 10 ft x 0.3333 ft
- Volume = 33.3333 cu ft = 1.2346 cu yd = 0.9439 m3
- Bags: 33.3333 cu ft / 0.6 cu ft per 80 lb bag = 55.56 -> 56 bags
- Weight: 33.3333 cu ft x 150 lb/ft3 = 5000 lb
Figures from concrete mix and bag yield tables, checked 31 August 2026. Its 9 worked examples are re-run on every release, last on 15 September 2026. What changed · how reference data is kept current
Sources and references
7 sources
Keep this result
Save it, change one figure, then compare the two
The calculation stays free. Save this scenario, adjust one assumption, save that too, and put them side by side to see exactly what the change costs you. A free account keeps 5 scenarios and 2 comparisons; Personal makes both unlimited and adds exports and private links. Nothing is saved unless you press Save.
What the bag concrete calculator calculates
Computes concrete volume in cubic feet, cubic yards and cubic metres for slabs, footings, walls, columns, stairs and curbs, then the bags, ready-mix loads, weight, cement/sand/aggregate split and cost that volume implies.
How to use this bag concrete calculator
Enter Element being poured, How many identical elements, Length and Width. Volume updates as you type. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Volume, Volume including waste allowance and Order this much ready-mix.
The method follows QUIKRETE Concrete Mix No. 1101 Technical Data Sheet (bag yields, ASTM C138 density), ASCE/SEI 7-22, Table C3.1-1a Minimum Design Dead Loads (stone concrete 150 lb/ft3 reinforced, 144 lb/ft3 plain), ASTM C150/C150M Standard Specification for Portland Cement (94 lb US bag), Portland Cement Association, Design and Control of Concrete Mixtures, 16th ed. (nominal volumetric proportioning, 94 lb = 1 ft3 sack) and ACI 318-19, Building Code Requirements for Structural Concrete (Table 19.3.2.1 maximum water/cementitious ratios).
What you can compare
Change one input at a time to see how it affects Volume, Volume including waste allowance and Order this much ready-mix. The inputs you can vary are Element being poured, How many identical elements, Length, Width, Thickness / depth and Height.
Understanding Volume, Volume including waste allowance and Order this much ready-mix
Footing, wall and column dimensions must come from a design by a qualified engineer or from a prescriptive table in the code adopted locally (e.g. IRC Table R403.1). This tool quantifies concrete for dimensions you supply; it does not size structural elements.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How do I calculate how many bags of concrete I will need?
Computes concrete volume in cubic feet, cubic yards and cubic metres for slabs, footings, walls, columns, stairs and curbs, then the bags, ready-mix loads, weight. Open “How this is worked out” beside the result to see each step for your own figures.
How many 80 lb bags is 2 yards of concrete?
On the figures this page opens with — length 10, width 10, thickness / depth 4 and waste / over-order allowance 0% — the volume is 1.2346 yd3. No single number fits everyone: change any figure above and the answer updates as you type, with each step of the arithmetic beside it.
How much concrete does a 50 lb bag cover?
It needs Element being poured, How many identical elements, Length, Width, Thickness / depth and Height. Nothing else is required, and the figures stay in your browser.
What information do I need for the bag concrete calculator?
You need Element being poured, How many identical elements, Length, Width, Thickness / depth, Height, Diameter (round column / Sonotube) and Number of steps. The page opens with default figures that give volume of 1.2346 yd3, so you can see the scale before entering your own.
What does this bag concrete calculator show?
It shows Volume, Volume including waste allowance, Order this much ready-mix, Rounded up to the quarter yard, Bags needed, Total weight of dry bags, Weight of the finished concrete and Ready-mix truck loads, with the working and any warnings for your entries.
Can I check how the bag concrete calculator result was calculated?
Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.