Concrete Calculator
Calculate concrete for slabs, walls, round footings, curb & gutter, or stairs. Get volume, weight, and bag requirements with flexible unit options.
*This calculator provides an estimate only. Always consult with a professional for final requirements.
Slabs & Walls
Perfect for driveways, patios, sidewalks, foundation walls, and retaining walls.
Round Footings
Ideal for column footings, pier foundations, and hole columns. Supports hollow designs.
Curb & Gutter
Perfect for street curbs, parking lot barriers, and drainage gutters with L-shaped cross-sections.
Stairs
Calculate concrete for outdoor stairs, steps, and landings with run, rise, and platform measurements.
Professional Concrete Calculator with Multiple Project Types
Our comprehensive concrete calculator supports multiple project types with flexible unit options. Calculate concrete requirements for slabs, walls, round footings, curb & gutter, and stairs using feet, inches, yards, meters, or centimeters for each dimension.
Key Features
- • Calculate volume in cubic feet, cubic yards, and cubic meters
- • Estimate weight in pounds and kilograms
- • Determine 60 lb and 80 lb bag quantities
- • Support for multiple project types and quantities
- • Flexible unit selection for each dimension
- • Four specialized calculators: slabs/walls, round footings, curb & gutter, and stairs
Supported Project Types
- • Slabs & Walls: Driveways, patios, sidewalks, foundation walls, retaining walls
- • Round Footings: Column footings, pier foundations, round posts, hole columns
- • Curb & Gutter: Street curbs, parking lot barriers, drainage gutters, L-shaped barriers
- • Stairs: Outdoor steps, landings, entry stairs, garden stairs with run/rise measurements
- • Hollow Structures: Support for inner diameter calculations
- • Commercial Projects: Any rectangular, round, L-shaped, or stepped concrete structure
How to Calculate Concrete Requirements
Step-by-Step Process
- 1. Measure Your Project: Get accurate length, width, and thickness measurements in feet and inches (or meters and centimeters).
- 2. Enter Dimensions: Input your measurements into the calculator. Use the quantity field for multiple identical structures.
- 3. Review Results: Get instant calculations for volume, weight, and bag quantities.
- 4. Plan Your Order: Use the cubic yard measurement for ready-mix concrete or bag counts for bagged concrete.
Pro Tips for Accurate Calculations
- • Always add 5-10% extra concrete for waste and spillage
- • Double-check your thickness measurements - this greatly affects volume
- • For irregular shapes, break them into rectangular sections
- • Consider the concrete strength requirements for your project
- • Factor in delivery time constraints for ready-mix concrete
Frequently Asked Questions
How do I calculate concrete volume?
To calculate concrete volume, multiply length × width × thickness. Convert thickness from inches to feet by dividing by 12. For example: 10 ft × 8 ft × (4 inches ÷ 12) = 26.67 cubic feet.
How many bags of concrete do I need?
Divide the total weight of concrete needed by the bag weight. For 60 lb bags: total weight ÷ 60. For 80 lb bags: total weight ÷ 80. Always round up to the nearest whole bag.
What is the weight of concrete per cubic foot?
This calculator uses 133 pounds per cubic foot, which is a standard density for typical concrete mixes used in residential construction.
How do I convert cubic feet to cubic yards?
Divide cubic feet by 27 to get cubic yards. For example: 81 cubic feet ÷ 27 = 3 cubic yards. Concrete is often sold by the cubic yard.
Can I use this calculator for footings and walls?
Yes! This calculator works for any rectangular concrete structure including slabs, square footings, and walls. Just enter the length, width, and thickness dimensions.
How do I calculate round footings or columns?
Switch to the 'Round Footings' tab and enter the outer diameter, inner diameter (0 for solid), and height. The calculator uses the formula π × (outer_radius² - inner_radius²) × height.
What units can I use for each dimension?
Each dimension (length, width, thickness, diameter, height) can be set independently to feet, inches, yards, meters, or centimeters for maximum flexibility.
Can I calculate hollow round footings?
Yes! Enter the outer diameter and inner diameter. For solid columns, leave the inner diameter as 0. The calculator will automatically account for the hollow space.
How do I calculate curb and gutter concrete?
Switch to the 'Curb & Gutter' tab and enter the curb depth, gutter width, curb height, flag thickness, and length. The calculator handles the complex L-shaped cross-section automatically.
What is flag thickness in curb and gutter?
Flag thickness refers to the horizontal slab portion of the gutter that extends from the vertical curb. This creates the L-shaped cross-section typical of street curbs and gutters.
How do I calculate concrete for stairs?
Switch to the 'Stairs' tab and enter the run (tread depth), rise (step height), width, platform depth, and number of steps. The calculator handles the complex stepped geometry automatically.
What are run and rise in stair calculations?
Run is the horizontal depth of each step (tread), and rise is the vertical height of each step. These measurements determine the stair's slope and total concrete volume needed.
Ready to Streamline Your Concrete Estimating?
This rebar calculator is just one tool. Flatwork's complete platform handles materials, labor, equipment, and smart upsells for complete project management.
