Concrete Volume Calculator

Complex construction projects rarely involve a single geometric shape; foundations, patio extensions, retaining piers, and entrance stairs are frequen

Construction

Slab / Flatwork Area

sq ft

Surface area of slab sections (enter 0 if none)

Slab Thickness

Uniform depth for slab sections in inches

Continuous Footing Length

Strip footing length (standard 16" wide × 8" deep section = 0.889 sq ft)

Round Piers / Columns

Count of 12" diameter × 4 ft deep circular piers (3.14 cu ft each)

Concrete Steps Count

Count of 4 ft wide cumulative steps (7" rise × 11" run = 3.06 cu ft/step avg)

Waste & Overage Factor

Combined project waste reserve (10% standard)

Formula & Methodology

Slab Volume = Area (sq ft) × (Thickness in ÷ 12) Footing Volume = Length (ft) × (16/12 ft) × (8/12 ft) Column Volume = Count × π × (Radius ft)² × Depth (ft) Steps Volume = [N(N+1) ÷ 2] × Stair Width (ft) × (Tread in ÷ 12) × (Riser in ÷ 12) Total to Order (cu yd) = ⌈(Sum of Volumes cu ft ÷ 27) × (1 + Waste % ÷ 100) ÷ 0.25⌉ × 0.25

Each structure utilizes tailored Euclidean geometric formulas: rectangular prisms for slabs and strip trenches, cylinders (πr²h) for Sonotube circular columns, and cumulative volumetric prisms for steps. All shape volumes in cubic feet are summed into a grand total, divided by 27 to obtain net cubic yards, augmented with a project waste reserve, and rounded strictly up to the supplier truck batch increment.

Combined Concrete to Order

3 cu yd

Overview

Complex construction projects rarely involve a single geometric shape; foundations, patio extensions, retaining piers, and entrance stairs are frequently poured together in a unified ready-mix dispatch. This Concrete Volume Calculator computes distinct geometric shapes side-by-side — flatwork slabs, continuous strip trenches, circular Sonotube columns, and solid stepped staircases — providing a comprehensive per-shape volume audit.

Estimates are for material planning and budgeting purposes only. This calculator does not provide structural engineering, architectural design, or official building code compliance advice. Always verify measurements, local building codes, and permit requirements with a licensed contractor or local building authority before purchasing materials or commencing construction.

Worked Examples

Example 1: Multi-Shape Project (Slab + Footing + 2 Columns + 3 Steps - Check Case)

Inputs: Slab = 100 sq ft @ 4", Footing = 20 ft, Columns = 2 (12"×4 ft), Steps = 3, Waste = 10%

Slab volume: 100 sq ft × (4/12 ft) = 33.33 cu ft = 1.23 cu yd.
Footing volume: 20 ft × (16/12) × (8/12) = 17.78 cu ft = 0.66 cu yd.
Columns volume: 2 × (π × 0.5² × 4) = 6.28 cu ft = 0.23 cu yd.
Steps volume: (3 × 4 / 2) × 4 ft × (11/12) × (7/12) = 6 × 4 × 0.9167 × 0.5833 = 12.83 cu ft = 0.48 cu yd.
Sum net cubic feet: 33.33 + 17.78 + 6.28 + 12.83 = 70.22 cu ft = 2.60 cu yd.
Add 10% waste buffer: 2.6009 × 1.10 = 2.8610 cu yd.
Round UP to supplier 0.25 yd increment: 3.00 cu yd.

Final Answer: 3.00 cu yd to order (Slab: 1.23, Footing: 0.66, Columns: 0.23, Steps: 0.48 cu yd)

Example 2: Deck Footings & Piers (40 ft Footing + 4 Columns @ 12"×4 ft with 10% Waste)

Inputs: Slab = 0 sq ft, Footing = 40 ft, Columns = 4, Steps = 0, Waste = 10%

Footing volume: 40 × (16/12) × (8/12) = 35.56 cu ft = 1.32 cu yd.
Columns volume: 4 × (π × 0.25 × 4) = 12.57 cu ft = 0.47 cu yd.
Sum net volume: 35.56 + 12.57 = 48.13 cu ft ÷ 27 = 1.7825 cu yd.
Add 10% waste: 1.7825 × 1.10 = 1.9607 cu yd.
Round UP: 2.00 cu yd.

Final Answer: 2.00 cu yd to order (1.32 cu yd strip footing + 0.47 cu yd columns)

Example 3: Patio Slab with Entrance Steps (200 sq ft Slab @ 4" + 4 Steps with 8% Waste)

Inputs: Slab = 200 sq ft @ 4", Footing = 0 ft, Columns = 0, Steps = 4, Waste = 8%

Slab: 200 × (4/12) = 66.67 cu ft = 2.47 cu yd.
Steps (4 steps): (4 × 5 / 2) × 4 × (11/12) × (7/12) = 10 × 2.1389 = 21.39 cu ft = 0.79 cu yd.
Sum: 66.67 + 21.39 = 88.06 cu ft ÷ 27 = 3.2613 cu yd.
Add 8% waste: 3.2613 × 1.08 = 3.5222 cu yd.
Round UP: 3.75 cu yd.

Final Answer: 3.75 cu yd to order (Slab: 2.47 cu yd; Steps: 0.79 cu yd)

How to Use This Calculator

Enter your slab or flatwork surface area in square feet and specify slab depth in inches.

Enter the linear footage of any perimeter strip footings planned.

Enter the count of 12-inch round pier columns or post footings.

Enter the count of concrete entrance steps.

Review the line-item breakdown table displaying cubic yardage per shape alongside the aggregated truck order.

Reference Table

Project Scope	Slab Vol	Footing Vol	Piers Vol	Steps Vol	Total Order (10% Waste)
Slab + Footing + 2 Piers + 3 Steps	1.23 cu yd	0.66 cu yd	0.23 cu yd	0.48 cu yd	3.00 cu yd
200 sq ft Slab + 4 Steps	2.47 cu yd	0.00 cu yd	0.00 cu yd	0.79 cu yd	3.75 cu yd
50 ft Footing + 4 Piers	0.00 cu yd	1.65 cu yd	0.47 cu yd	0.00 cu yd	2.50 cu yd
150 sq ft Slab + 2 Piers	1.85 cu yd	0.00 cu yd	0.23 cu yd	0.00 cu yd	2.50 cu yd
300 sq ft Slab + 30 ft Footing	3.70 cu yd	0.99 cu yd	0.00 cu yd	0.00 cu yd	5.25 cu yd
Full Foundation Package	4.94 cu yd	3.30 cu yd	0.93 cu yd	1.02 cu yd	11.25 cu yd

Frequently Asked Questions

Why should I calculate different concrete shapes in a single tool?

Ready-mix batch plants charge delivery and minimum fees per truck dispatch. Calculating all job components simultaneously ensures you order enough concrete to pour the entire project in one visit, preventing short-load penalties and scheduling delays.

What are the assumed dimensions for the continuous footing line item?

The footing section assumes standard residential strip footing dimensions of 16 inches wide by 8 inches deep (0.8889 square feet of cross-sectional area per linear foot). Confirm your specific structural requirements with local plans.

What size round columns does this calculator assume?

The tool models standard 12-inch diameter circular columns or Sonotubes poured 4 feet deep below the frost line, which yield approximately 3.14 cubic feet (0.116 cubic yards) of concrete per pier.

How does the tool calculate the volume of concrete steps?

Steps are computed using cumulative stair geometry (width × tread depth × cumulative riser height per step) rather than a simple uniform block, reflecting the true triangular stepped cross-section.

Can I set unused shape fields to zero?

Yes. If your project has no steps or round piers, simply leave those fields as 0. The calculator computes the exact volume for only the active shapes entered.