Concrete Calculator

Instantly estimate the concrete volume and bag requirements for slabs, footings, and more. Enter your dimensions and get accurate results for your project.

Understanding Concrete Calculations

Concrete is a fundamental material in construction, composed of cement, sand, aggregate, and water. Accurate calculation of concrete volume is crucial for cost efficiency, structural integrity, and project success. This calculator helps you estimate the amount of concrete required for slabs, footings, columns, and more, reducing waste and ensuring you order the right amount for your project.

The two most common shapes for concrete pours are rectangular (slabs, footings) and circular (columns, piers). For rectangular shapes, volume is calculated as Length × Width × Depth. For circular shapes, it is π × Radius² × Depth. Always measure dimensions in feet for consistency, and convert inches to feet where necessary (e.g., 4 inches = 0.33 feet).

  • 1 cubic yard = 27 cubic feet
  • 80 lb bag ≈ 0.6 cubic feet
  • 60 lb bag ≈ 0.45 cubic feet
  • Order 5-10% extra to account for spillage and overage
  • Ready-mix trucks typically deliver 8-10 cubic yards per load

How This Tool Works

The Concrete Calculator takes your input dimensions and shape, then applies the correct formula to estimate the total volume of concrete needed. For rectangular pours, it multiplies length, width, and depth. For circular pours, it uses the diameter to find the radius, then calculates the volume using π × r² × depth. The tool then converts the result to cubic yards and estimates the number of 80lb and 60lb bags required, rounding up to ensure you have enough material.

All calculations are performed instantly in your browser, and no data is stored or shared. The tool is designed for both professionals and DIY users, providing fast, reliable results for any project size.

Key Features

  • Supports Rectangular and Circular Shapes: Easily switch between slab and column calculations.
  • Instant Results: Get volume, cubic yards, and bag estimates as soon as you enter your measurements.
  • Mobile Friendly: Fully responsive design for use on any device.
  • Bag Estimator: Calculates the number of 80lb and 60lb bags needed for your project.
  • Waste Allowance: Built-in recommendation to order extra for spillage and overage.
  • Privacy First: All calculations are local to your device.
  • Simple Interface: Clean, intuitive layout for quick use on-site or in the office.

Common Use Cases

  • Driveways and Patios: Estimate concrete for new slabs or repairs.
  • Footings and Foundations: Calculate volume for structural supports.
  • Columns and Piers: Determine material for round forms.
  • Sidewalks and Walkways: Plan for even, durable surfaces.
  • DIY Projects: Small pours for garden beds, posts, or steps.
  • Construction Professionals: Quick estimates for bids and planning.

Step-by-Step Guide

  1. Select Shape: Choose rectangular for slabs/footings or circular for columns/piers.
  2. Enter Dimensions: Input length, width, and depth for rectangular; diameter and depth for circular.
  3. Click Calculate: Press the button to see your results instantly.
  4. Review Results: View cubic feet, cubic yards, and bag estimates. Adjust for waste as needed.
  5. Order Materials: Use the results to order the correct amount of concrete or bags for your project.

For best results, double-check your measurements and always round up your order to avoid shortages. Consult with your supplier for large or complex projects.