Concrete Yardage Calculator
Calculate cubic yards of concrete to order for slabs, round columns, or continuous footings, with a waste factor matching standard take-off practice.
10% covers a typical slab. 5% for a small clean pour; 15%+ for stepped footings or pump-truck jobs.
About this tool
Estimating concrete is one of the few decisions on a job where you cannot easily fix the answer after the fact. Order short and the truck has to come back. Order long and you pay for material that goes in the wash-out pit. This calculator handles the three forms most residential and light-commercial pours need: a flat slab, a round column or pier, and a continuous strip footing.
For each form, you enter the dimensions in the units a contractor actually thinks in: feet for plan dimensions, inches for thickness and depth, inches of diameter for piers. The result is cubic yards rounded to the nearest hundredth, with a separate cubic-yards-before-waste figure so you can see how much of the order is the safety margin.
The waste factor defaults to 10%, which covers a typical slab with normal forms and average finish quality. Tighten it to 5% on a small clean slab where you trust the formwork and a screed crew that does not over-pull. Loosen it to 15% on a job with stepped footings, complex penetrations, or anything that involves a pump truck reaching over obstructions. See the methodology page for how we derive these defaults.
How it works
Volume comes from the geometry of the form, then converts to cubic yards by dividing by 27 (since 1 yd³ = 27 ft³).
- Slab: V = length × width × thickness, all converted to feet.
- Round column: V = π × r² × height, where r = diameter / 2 (both converted to feet).
- Continuous footing: V = length × footing width × footing depth, with the cross-section dimensions converted from inches to feet.
The waste factor multiplies the geometric volume to give the final order quantity. The geometric formulas come from standard concrete take-off practice as described in ACI 318 Chapter 26 (concrete materials) and the PCA Design and Control of Concrete Mixtures handbook.
Examples
A 12×14 patio slab at 4 inches thick. The geometric volume is 56 cubic feet, which is 2.07 cubic yards before waste. With a 10% waste factor the order is 2.28 yd³. Round up at the truck since ready-mix suppliers typically deliver in 0.25 yd³ increments with a 1 yd³ minimum.
A 16-inch sonotube pier 8 feet tall. Small volume near the minimum delivery; if you are pouring a single pier it usually pays to batch it with another pour or mix on-site with bagged concrete.
A 40-foot continuous strip footing with 16 in wide by 12 in deep cross-section. Footings often need a higher waste factor when the trench bottom is uneven; consider 15% if the excavation shows irregular grade.
When to use
Use this when you are sizing a truck delivery for a residential slab, a deck pier set, or a strip footing under a small addition. Pair it with the gravel and fill calculator when prepping the sub-base, since the gravel order usually goes on the same delivery ticket. For anything load-bearing on a permit set, the engineer's drawings drive the order, not this tool.
Related concepts
- ACI 318 : Building code requirements for structural concrete
- Waste factor practice
Frequently asked questions
Why does the result include a separate "before waste" number?
So you can see what the geometry alone gives you and decide for yourself whether the default waste factor matches your job conditions. On a tight pour with an experienced crew, you may want to dial it down. On anything pump-trucked, you may want to dial it up.
Can I use this for stamped or colored concrete?
The volume math is the same. Stamped or colored concrete usually has a slightly higher waste factor (15-20%) because of finishing rework. Adjust the waste field accordingly.
Does this account for rebar displacement?
No, and you should not subtract for it. Rebar volume is small enough relative to the pour that it is treated as zero in standard take-off practice.
Sources
- ACI 318, Building Code Requirements for Structural Concrete
(primary, accessed Apr 16, 2026)
American Concrete Institute building code, primary reference for structural concrete design and take-off practice.
- PCA Design and Control of Concrete Mixtures
(primary, accessed Apr 16, 2026)
Portland Cement Association reference handbook for mix design and placement practice.
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