Calculators › Construction & Trades
Free calculatorLive resultsSteps and sourcesEmbed on your site, free

Concrete Calculator

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.

Volume
1.2346 yd3
Concrete Calculator
Volume
33.333 ft3
Volume
0.9439 m3
Volume including waste allowance
33.333 ft3
Order this much ready-mix
1.2346 yd3
Rounded up to the quarter yard
1.25 yd3
Bags needed
56
Total weight of dry bags
4,480 lb
Weight of the finished concrete
5,000 lb
Weight of the finished concrete
2.500 ton (US short)
Weight of the finished concrete
2,268.0 kg
Weight of the finished concrete
2.268 t (metric)
Ready-mix truck loads
1
Finished surface area
100.00 ft2
Delivery and short-load fees
0.00 USD
Volume per element
33.3333 ft3
Worked out from QUIKRETE Concrete Mix No. 1101 Technical Data Sheet (bag yields, ASTM C138 density) and 6 other sources.
No waste allowance applied. Ready-mix is normally ordered 5-10% over the theoretical volume.
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.

Your figures

Updates as you type
e.g. 12 identical pier footings, or 1 slab.
Slab/footing/wall/curb length, or column side.
Wall or column height.
Used only when the element is "I already know the volume".
Covers subgrade irregularity, spillage and over-excavation. 5-10% is normal for a formed pour on a prepared base.
Yields are from the QUIKRETE Concrete Mix No. 1101 data sheet (0.0075 cu ft of concrete per pound of dry mix).
Use the yield printed on your own bag if it differs (fast-setting, high-strength and crack-resistant mixes vary).
ASCE/SEI 7 Table C3.1-1a: 150 lb/ft3 reinforced stone concrete, 144 lb/ft3 plain. Lightweight mixes run 90-120. In metric those are 2400 and 2300 kg/m3.
Normalweight concrete is 150 lb/ft3 or, equivalently, about 2400 kg/m3.
Only needed if you are batching from separate cement, sand and stone rather than buying concrete.
Dry loose ingredient volume needed per unit of placed wet concrete. 1.52-1.57 is standard practice.
Mass of mixing water per unit mass of cement. ACI 318-19 Table 19.3.2.1 caps w/cm at 0.50 for concrete exposed to freezing and thawing or to de-icing chemicals. Set 0 to skip the water figure.
Used only to turn the batched sand volume into a weight. 100 lb/ft3 is the US EPA table figure for dry sand; use your supplier ticket when you have one.
US EPA table figure for crushed stone is 100 lb/ft3.
Use this instead of the price per cubic yard where concrete is sold by the cubic metre.
Flat charge the supplier adds per delivery, on top of the concrete itself.
Orders under this size attract the short-load fee below. Leave at 0 if your supplier does not charge one.
Quoted rate for forming, placing and finishing, applied to the finished surface area. Ask your contractor; rates are local.

How this is worked out

4 steps
  1. slab: 10 ft x 10 ft x 0.3333 ft
  2. Volume = 33.3333 cu ft = 1.2346 cu yd = 0.9439 m3
  3. Bags: 33.3333 cu ft / 0.6 cu ft per 80 lb bag = 55.56 -> 56 bags
  4. 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
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)
7-22
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)
ACI 318-19, Building Code Requirements for Structural Concrete (Table 19.3.2.1 maximum water/cementitious ratios)
318-19
U.S. EPA, Standard Volume-to-Weight Conversion Factors (loose bulk density of dry sand and crushed stone, 100 lb/ft3)
NIST Special Publication 811, Guide for the Use of the International System of Units (exact lb-to-kg and ft-to-m conversions; the US gallon as 231 cubic inches)

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.

1 · Calculate2 · Save3 · Compare4 · Export5 · Share
Open workspace

What the 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 Concrete Calculator

Enter Element being poured, How many identical elements, Length and Width. Volume updates as you type, and “Use a worked example” loads checked figures you can adjust. 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).

10 ft x 10 ft slab, 4 in thick example

With Element being poured: slab, Length: 10, Width: 10, Thickness / depth: 4, the calculator returns Volume: 33.333333, Volume: 1.234568, Bags needed: 56. This example is checked against an independent source in the test suite.

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.

Embed this calculator on your website

Copy this code into any page. The calculator appears with the figures currently entered, sizes itself to fit, and a small credit line links back here. Free, no account, no ads inside it, no tracking of your readers. Set your own figures and fixed fields; Personal removes the credit line, sets your colour and shows you which sites use it.

Preview

See something wrong? Report a problem with this calculator

Frequently asked questions

What information do I need for the 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 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 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.

Related calculators

Block Concrete CalculatorConstruction & TradesConcrete Floor CalculatorConstruction & TradesConcrete Floor Cost CalculatorConstruction & TradesConcrete Cost CalculatorConstruction & Trades
View all related calculators7 more
Bag Concrete CalculatorConstruction & TradesCinder Block Concrete CalculatorConstruction & TradesApplications CalculatorConstruction & TradesGravel CalculatorConstruction & TradesMulch CalculatorConstruction & TradesCylinder Volume Formula CalculatorGeometry & MeasurementVolume CalculatorGeometry & Measurement