MyYardCalc
Construction · Material planning

Concrete Calculator

Calculate concrete volume for slabs, footings and round or hollow columns. Estimate ready-mix yardage and bags using the labeled mixed yield.

All construction tools ↗

Your project

US & metric

Example values are filled in. Replace them with your measurements.

ft
ft
ft
in
%

An editable purchasing margin, not a measured compaction rate.

cu ft

Use the mixed yield printed on your concrete bag.

lb / cu yd

Optional. Enter the density of this product to estimate weight.

$
$ / cu yd
$

Enter 0 if included. Bulk cost remains blank until delivery is specified.

Enter your measurements

—

The calculation

Volume = net area × depth × (1 + extra ÷ 100). Weight = volume × supplier density.

  • Enter your supplier’s bulk density to show weight. Volume alone cannot determine tons.
  • 10% extra is included once. Confirm supplier minimums and delivery increments.

Saved on this device

Only estimates you choose to save are stored here.

    Measure with a little context

    How to use this concrete calculator

    Select the geometry of the pour and enter actual dimensions. For columns, the thickness field represents the full column height.

    Bag quantities use mixed yield, not dry bag volume or weight. Confirm ready-mix minimums and delivery charges before ordering.

    Volume = net area × depth × (1 + extra ÷ 100). Weight = volume × supplier density.

    A worked example

    With the example values shown below, the calculated result is 1.304 cu yd. These are demonstration inputs, not installation specifications.

    View the example measurements
    • Length / outside diameter: 12 ft
    • Width: 8 ft
    • Inside diameter: 1 ft
    • Identical pours: 1
    • Thickness / column height: 4 in
    • Extra allowance: 10 %
    • Yield per bag: 0.6 cu ft

    From estimate to order

    Whole packages and pieces round up; measured lengths, areas and volumes keep full precision during calculation. Match the product dimensions and units to your quote, and check cuts, minimum orders and delivery before purchasing.

    Read our formulas, rounding rules and limitations →

    Concrete planning questions

    How do I convert concrete yards to bags?

    Multiply cubic yards by 27 for cubic feet, then divide by the mixed yield printed on the bag and round up. The yield is the volume of prepared concrete, not the dry bag volume or bag weight. Different products and bag sizes have different yields.

    How do I calculate a round column or hollow cylinder?

    Select the corresponding pour shape and enter the outside diameter. A hollow cylinder also needs the inside diameter. The thickness or column-height field uses inches in US mode or centimeters in metric mode, so convert a full column height before entering it.

    How many 80 lb bags of concrete are in a cubic yard?

    Use the mixed yield on the actual product label. If an 80 lb bag yields 0.60 cubic feet, 27 ÷ 0.60 = 45 bags supply one cubic yard before allowance. Bag weight alone is not enough to guarantee that yield. Other mix types and bag sizes can have different yields.

    Calculation notes updated . Formulas, sources and limitations.

    Keep your project moving.

    All construction tools →

    Concrete slab calculator

    Work out concrete yardage and bag yield for a flat slab.

    Rebar calculator

    Estimate a rectangular reinforcement grid, bar lengths and conservative stock counts.

    Block calculator

    Estimate concrete masonry units from wall area and joint dimensions.

    Gravel calculator

    Estimate gravel volume, bags and supplier-based weight for paths and driveways.