Concrete Volume Calculator | Free Construction Calculators
Calculate concrete volume for any shape including rectangular slabs, circular pads, and cylindrical columns. Our professional concrete volume calculator helps contractors, engineers, and DIY builders accurately estimate cubic yards, cubic feet, and bags needed for footings, columns, walls, foundations, piers, and complex concrete forms. Select your shape, enter dimensions, and get instant results with detailed breakdowns including weight, ready-mix quantities, and bagged concrete requirements. Perfect for structural engineering, construction estimation, and accurate concrete ordering for projects of any size.
Multiple Shapes
Calculate for rectangular, circular, and cylindrical concrete forms
Precise Formulas
Industry-standard calculations for accurate material estimates
Complete Results
Get cubic yards, cubic feet, weight, and bags in one calculation
How to Use This Calculator
- Select the shape of your concrete form (rectangular, circular, or cylindrical)
- Enter the required dimensions in feet (length, width, height for rectangles; diameter and height for circles)
- Click Calculate to see volume in cubic yards, cubic feet, and total weight
- Review bags needed for both 60-lb and 80-lb bag sizes
- Add 5-10% extra for waste, spillage, and irregular surfaces
Volume Formulas by Shape
Rectangular/Square: Volume = Length × Width × Height
Circular Slab: Volume = π × (Diameter ÷ 2)² × Height
Cylindrical: Volume = π × (Diameter ÷ 2)² × Height
Conversion: Cubic yards = Cubic feet ÷ 27
About Concrete Volume Calculations
Accurate concrete volume calculations are fundamental to successful construction projects. Whether pouring rectangular footings, circular columns, cylindrical piers, or complex structural forms, knowing the precise volume prevents material waste and costly shortages. This calculator uses industry-standard formulas to compute exact cubic yardage for rectangular, circular, and cylindrical concrete shapes.
Rectangular calculations apply to slabs, footings, walls, foundations, and beam forms where you have defined length, width, and height dimensions. Circular calculations are essential for round pads, pizza ovens, circular patios, and foundation piers. Cylindrical calculations determine concrete needed for columns, support posts, concrete-filled steel tubes (CFT), and round sonotubes commonly used in foundation and deck construction.
Professional contractors break complex shapes into simpler geometric forms, calculate each section individually, then sum the volumes for total concrete requirements. For irregular or organic shapes, divide the form into multiple rectangles and circles that approximate the overall shape. Always add 5-10% overage for waste, spillage, and form irregularities. Ready-mix concrete trucks deliver in 0.5 cubic yard increments, so round up accordingly when placing orders.
Common Applications by Shape
Frequently Asked Questions
How do I calculate concrete volume for a cylindrical column?
For cylindrical columns and piers, measure the diameter and height of the form. Use the formula: Volume = π × (radius)² × height, where radius = diameter ÷ 2. For example, a 12-inch diameter, 8-foot tall sonotube requires: π × (0.5 ft)² × 8 ft = 6.28 cubic feet = 0.23 cubic yards. Round up to 0.25 cubic yards for ordering. For multiple columns, calculate each individually and sum the total volume, adding 10% extra for overfill and waste.
What's the difference between circular and cylindrical calculations?
Both use the same formula (π × radius² × height), but the terminology differs by application. Circular typically refers to horizontal applications like round slabs, patios, or pads where you're looking down at a circle. Cylindrical refers to vertical applications like columns, posts, or tubes where you're viewing the side of a cylinder. The calculator produces identical results for both shapes when using the same diameter and height values.
How do I calculate volume for an irregularly shaped concrete form?
Break irregular shapes into multiple simple shapes (rectangles and circles), calculate each section separately, then add volumes together. For example, an L-shaped footing becomes two rectangles. A rounded corner patio is a rectangle plus a quarter-circle. For truly irregular organic shapes, divide the area into a grid of small rectangles that approximate the shape. Use the shape that best fits each section, calculate all sections, sum the total, then add 10% extra for irregular forms.
How many cubic feet are in a cubic yard of concrete?
One cubic yard contains exactly 27 cubic feet. This comes from the cubic relationship: 1 yard = 3 feet, so 1 cubic yard = 3 ft × 3 ft × 3 ft = 27 cubic feet. Ready-mix concrete is sold by the cubic yard, while bagged concrete coverage is listed in cubic feet. To convert cubic feet to cubic yards, divide by 27. To convert cubic yards to cubic feet, multiply by 27. This calculator provides both measurements for convenient ordering and estimation.
What concrete volume requires ready-mix versus bagged concrete?
Use bagged concrete for projects under 1 cubic yard (27 cubic feet), which equals about 45 bags of 80-lb mix. Bagged concrete works well for: small footings, fence posts, repairs, and tube forms. Switch to ready-mix for projects over 1 cubic yard, large slabs, multiple footings, or anything requiring more than 40-50 bags. Ready-mix provides consistent quality, saves mixing labor, arrives pre-mixed, and costs less per cubic yard for larger volumes. Most suppliers have 1 cubic yard minimums with better pricing starting at 2-3 cubic yards.
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Professional Volume Calculation Tips
- Measure accurately: Use a quality tape measure and double-check all dimensions before ordering
- Account for rebar: Reinforcement displaces minimal concrete, typically less than 1-2%
- Break down complex shapes: Divide irregular forms into simple rectangles and circles
- Add 10% for irregular forms: Non-uniform shapes require extra material for overfill
- Round up for ready-mix: Trucks deliver in 0.5 yard increments, order next highest amount
- Consider form variations: Wood forms may bow or have inconsistent dimensions
- Use sonotube charts: Cardboard tube manufacturers provide exact volume per linear foot
- Plan for multiple pours: Calculate each section separately for staged construction
Quick Volume Reference Guide
Sonotube Volumes (per linear foot)
- 6-inch diameter: 0.196 cu ft per foot
- 8-inch diameter: 0.349 cu ft per foot
- 10-inch diameter: 0.545 cu ft per foot
- 12-inch diameter: 0.785 cu ft per foot
- 16-inch diameter: 1.396 cu ft per foot
- 20-inch diameter: 2.182 cu ft per foot
Common Footing Sizes
- 12" × 12" × 10 ft: 10.0 cu ft = 0.37 cu yd
- 16" × 8" × 10 ft: 8.9 cu ft = 0.33 cu yd
- 18" × 10" × 10 ft: 12.5 cu ft = 0.46 cu yd
- 24" × 12" × 10 ft: 20.0 cu ft = 0.74 cu yd
- 30" × 12" × 10 ft: 25.0 cu ft = 0.93 cu yd