How many cubic feet are in a cubic yard?

27. A yard is 3 feet, and volume converts by the cube of the linear factor: 3 x 3 x 3 = 27 cubic feet per cubic yard.

How many bags of concrete make a cubic yard?

Roughly 45 eighty-pound bags or 60 sixty-pound bags, based on typical bag yields. Check the specific bag's yield figure, since mixes vary, and buy a few extra bags for waste.

How do I calculate cubic yards for a stair footing or pad?

Multiply length by width by thickness in consistent units, then divide by 27. For example, a pad 6 feet by 4 feet by 4 inches thick: convert 4 inches to 1/3 foot, so 6 x 4 x 0.333 = 8 cubic feet, divided by 27 = 0.30 cubic yards.

How much does a cubic yard of concrete weigh?

About 4,000 pounds, or roughly 2 tons. That weight is why suppliers deliver in trucks rather than bags and why the subgrade under a pad needs proper compaction.

How much extra concrete should I order for waste?

Add 5 to 10 percent over the calculated volume for small forms and footings with irregular excavation. Use the higher end when the hole bellied out or the forms are slightly oversized.

What is the minimum order for ready-mix concrete?

Most suppliers have a minimum order, commonly in the range of one to a few yards, and charge a short-load fee for smaller orders. Confirm with your local supplier, and compare against bagged mix for pours well under a yard.

Does this calculator work for gravel, topsoil, and mulch too?

Yes. The math is identical for any bulk material: volume in cubic yards equals length times width times depth divided by 27, and bulk suppliers price these materials by the yard.

Cubic Yard Calculator

What Is the Cubic Yard Calculator?

Our free cubic yard calculator converts the length, width, and depth of any shape into cubic yards so you can order the right amount of concrete, gravel, topsoil, mulch, or fill for your stair project. A cubic yard is the standard unit for bulk construction materials in the United States: it equals 27 cubic feet, and suppliers price and deliver concrete, stone, and soil by the yard. Get this number wrong and you either stall the pour waiting on a second truck or pay to dispose of material you never needed. For stair work, the calculator is most useful for estimating concrete in footings, pads, and landing slabs, plus gravel base layers and topsoil backfill around garden stairs. Small pours under about one yard often make more sense with bagged mix, where one cubic yard requires roughly 45 eighty-pound bags or 60 sixty-pound bags, while larger pours justify a ready-mix truck. Either way, every estimate starts with the same honest math: length times width times depth, converted correctly, with a realistic waste allowance built in.

How to Use This Calculator

Enter the length, width, and depth of the area or form you need to fill, choosing consistent units for all three measurements.
If your measurements are in inches, let the calculator convert them to feet automatically, since volume in cubic feet is the cleanest intermediate step.
Review the result in cubic yards alongside the cubic-feet and cubic-inch equivalents so you can sanity-check the math against your form size.
For a stair footing or concrete pad, measure the actual form length and width, plus the planned thickness (4 inches is a common pad depth).
If the pour is small (well under one yard), use the bag-count estimate to compare bagged mix against calling a ready-mix supplier.
Round the final number up rather than down, because a short order creates a cold joint or a second delivery fee.
Add a 5 to 10 percent waste factor for irregular subgrade, excavation that bellied out, or forms that are slightly larger than drawn.

Cubic Yard Calculator