Title: Concrete calculator | Cercha
Description: Estimate cubic yards for slabs, rectangular footings, and round columns. Enter dimensions and waste, then check quantities before ordering.
Canonical: https://cercha.pages.dev/tools/concrete-calculator/
# Concrete calculator
Construction calculators
Check cubic yards from your pour dimensions before you call the concrete supplier.
You need a pour quantity before you call dispatch or compare your concrete sub’s takeoff. Choose a slab, rectangular footing, or solid round column. Enter its dimensions, identical-piece count, and waste allowance to estimate cubic yards.
## Measure the filled shape
For a slab, enter length and width in feet and thickness in inches. For a footing, use length in feet with width and depth in inches. For a column, enter the inside filled diameter in inches and filled height in feet. Check the unit beside each field before copying dimensions from your site notes.
Use the quantity field only for pieces with identical dimensions. Split a stepped footing or changing slab thickness into separate sections. Record each section on your sketch so another person can trace the volume back to the pour.
## Check the formula and allowance
[Sakrete’s estimating guide](https://www.sakrete.com/blog/post/estimating-bagged-concrete-jobs/) calculates rectangular volume and divides cubic feet by twenty-seven to obtain cubic yards. This tool converts inches to feet before multiplying. For columns, it derives volume from circular area times height: pi times radius squared times height.
The calculator multiplies net volume by one plus your waste percentage divided by one hundred. [NRMCA’s ordering guide](https://www.nrmca.org/wp-content/uploads/2021/01/31pr.pdf) discusses contingency above plan quantities. Choose the allowance with the people responsible for the pour rather than treating the initial zero as an ordering recommendation.
## Read the result before placing the order
For example, a nine-by-nine-foot slab at four inches thick contains one cubic yard. Entering ten percent waste produces 1.10 cubic yards. The tool’s upward quarter-yard option gives 1.25 cubic yards. Confirm that increment with the supplier.
For one delivery covering several shapes, add net volumes before applying one shared allowance and order rounding. Adding separate rounded orders changes the total. The model does not subtract reinforcement, embedded posts, or voids; keep those assumptions with the takeoff.
## Check the inputs and results
| Input | Unit and accepted values |
| --- | --- |
| Shape | Slab, rectangular footing, or solid round column |
| Slab dimensions | Length and width: feet, greater than zero through 10,000. Thickness: inches, greater than zero through 1,200. |
| Footing dimensions | Length: feet, greater than zero through 10,000. Width and depth: inches, greater than zero through 1,200. |
| Column dimensions | Diameter: inches, greater than zero through 1,200. Height: feet, greater than zero through 10,000. |
| Identical pieces | Whole count, 1 through 100,000 |
| Waste | Percent, 0 through 100 |
Enter positive dimensions and a whole piece count. Waste can be zero. The quarter-yard option rounds the full adjusted volume upward; confirm that increment with dispatch.
## Before you release the pour
Keep feet, inches, and cubic yards distinct; [NIST’s unit table](https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8) provides conversion references. Record the filled dimensions before comparing a supplier’s quantity.
For round forms, check the selected product’s dimensions and instructions against the [Sonotube round-form reference](https://www.sonoco.com/sites/default/files/files/Sonotube%C2%AE%20Round%20Concrete%20Forms%20product%20brochure.pdf). This calculator models a solid cylinder, without a widened base or hollow core.
Assign curing separately using [NRMCA’s curing guidance](https://www.nrmca.org/wp-content/uploads/2021/01/11pr.pdf). Confirm the permit checkpoint through [Raleigh’s inspection sequence](https://raleighnc.gov/permits/services/residential-inspections) or your local office before releasing the pour.
Review the takeoff with the [concrete sub](/trades/concrete/) and the [concrete supplier](/suppliers/concrete-and-masonry/). Use the [material-delivery guide](/guides/jobsite-material-delivery/) to assign site access and the receiver.
Return to the [construction tools hub](/tools/) for the other quantity checks and printable records.
## Where Cercha fits
Use the Cercha app’s Search filters to find a concrete trade by trade, ZIP code, and radius. Review portfolio photos and use Messages to discuss the pour scope. Keep the quantity check with your project notes.
- Shape: Slab
- Length (ft): 10
- Width (ft): 10
- Thickness (in): 4
- Identical pieces (count): 1
- Waste allowance (%): 0
Net volume (yd³): 1.234568; Volume with allowance (yd³): 1.234568; Estimated volume (yd³): 1.23; Rounded upward to 0.25 yd³: 1.25
## How this is calculated
Slab yd³ = L × W × T × q ÷ 324. Footing yd³ = L × W × D × q ÷ 3888. Column yd³ = π × d² × H × q ÷ 15552. Volume with allowance = net volume × (1 + w ÷ 100).
L and W are feet for slabs; T is inches. Footing L is feet, W and D are inches. Column d is inches, H is feet. q is pieces, w is percent. The cylinder equation is our geometric derivation. The quarter-yard ceiling is a display choice.
Volumes show six decimal places; the main estimate shows two. The order option rounds upward to a quarter cubic yard from the unrounded result. Confirm the supplier increment.
Ordinary displays round half up: an exact halfway value rounds upward. Display rounding never changes the purchase ceiling.
[Sakrete: Estimating Bagged Concrete Jobs](https://www.sakrete.com/blog/post/estimating-bagged-concrete-jobs/). Rectangular volume, cubic-inch to cubic-foot conversion, 27 cubic feet per cubic yard.
[National Ready Mixed Concrete Association: CIP 31: Ordering Ready Mixed Concrete](https://www.nrmca.org/wp-content/uploads/2021/01/31pr.pdf). Volume sold in cubic yards; 4% to 10% contingency above plan estimate.
[Sonoco: Sonotube Round Concrete Forms brochure](https://www.sonoco.com/sites/default/files/files/Sonotube%C2%AE%20Round%20Concrete%20Forms%20product%20brochure.pdf). Round concrete forms. Cylinder equation below is our geometric derivation, not a quoted manufacturer formula.
Estimate only. Dimensions must already be selected. This model does not subtract reinforcement, embedded posts, or voids. Confirm order increments with your supplier. For one delivery, sum net volumes before applying one allowance and ceiling.
Estimate only. No structural sizing, loads, spans, strengths, or code-compliance decisions are calculated.
Volume estimate only. Dimensions must already be selected. Confirm the allowance and delivery increment with your concrete supplier.
Print this calculator from the HTML page.
## Build your connections
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## Sources
1. Sakrete. (n.d.). *Estimating Bagged Concrete Jobs*. Retrieved October 14, 2026, from https://www.sakrete.com/blog/post/estimating-bagged-concrete-jobs/
2. National Ready Mixed Concrete Association. (n.d.). *CIP 31: Ordering Ready Mixed Concrete*. Retrieved October 14, 2026, from https://www.nrmca.org/wp-content/uploads/2021/01/31pr.pdf
3. NIST. (2025, August 18). *Guide to the SI, Appendix B.8*. https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8
4. Sonoco. (n.d.). *Sonotube Round Concrete Forms brochure*. Retrieved October 14, 2026, from https://www.sonoco.com/sites/default/files/files/Sonotube%C2%AE%20Round%20Concrete%20Forms%20product%20brochure.pdf
5. National Ready Mixed Concrete Association. (n.d.). *CIP 11 - Curing In-Place Concrete*. Concrete in Practice. Retrieved October 14, 2026, from https://www.nrmca.org/wp-content/uploads/2021/01/11pr.pdf
6. City of Raleigh. (2026, October 12). *Residential Inspections*. Raleighnc.gov. https://raleighnc.gov/permits/services/residential-inspections