Slab Concrete Calculator – Calculate Volume in Cubic Feet, Yards & Meters

Planning to pour a concrete slab? Whether it’s for a driveway, patio, garage floor, shed base, or foundation, accurate concrete estimation is essential to avoid delays and unnecessary costs.

Our Slab Concrete Calculator helps you quickly calculate how much concrete you need in:

• Cubic Feet (ft³)
• Cubic Yards (yd³)
• Cubic Meters (m³)

Just enter the Length (L), Width (W), and Thickness (H) in your preferred unit (Feet, Inches, Yards, or Meters), and get instant results.

In the United States, concrete is typically ordered in cubic yards, so knowing your yard requirement before contacting a ready-mix supplier is essential.

What Is a Concrete Slab?

A concrete slab is a flat, horizontal surface made from poured concrete. It is commonly used for:

• Residential foundations
• Driveways
• Sidewalks
• Patios
• Garage floors
• Basement floors
• Shed and workshop bases

Slabs distribute structural loads evenly and provide strong, durable support.

Slab Concrete Volume Formula

To calculate concrete volume for a slab, use this formula:

Volume = Length × Width × Thickness

Example:

If your slab is:

• 20 feet long
• 15 feet wide
• 4 inches thick

First convert thickness to feet:
4 inches ÷ 12 = 0.33 feet

Then:

20 × 15 × 0.33 = 99 cubic feet

Divide by 27 to convert to cubic yards:
99 ÷ 27 = 3.67 cubic yards

Our calculator performs these conversions automatically.

Standard Slab Thickness Guide

Here are common slab thickness recommendations:

• 4 inches – Walkways, patios, sheds
• 5 inches – Residential driveways
• 6 inches – Heavy vehicles, small trucks
• 8+ inches – Commercial or heavy equipment areas

Always consult local building codes before construction.

Why Accurate Slab Estimation Is Important

Ordering the correct amount of concrete helps you:

• Avoid job site delays
• Prevent cold joints from multiple pours
• Reduce waste
• Save money on materials
• Improve project efficiency

In the United States, ready-mix concrete is typically ordered in cubic yards, so knowing your yard requirement is critical.

How to Use the Slab Concrete Calculator

Using this slab concrete calculator is simple. Follow the step-by-step instructions below to get accurate concrete volume results for your project.

Step 1: Select Your Unit of Measurement

Choose your preferred unit before entering dimensions:

• Feet (FT)
• Inches (IN)
• Yards (YD)
• Meters (M)

Select the unit that matches how you measured your slab area. The calculator will automatically convert everything into cubic feet, cubic yards, and cubic meters.

Step 2: Enter the Length (L)

Measure the longest side of your slab area and enter it into the Length (L) field.

Tips:

• Measure inside the formwork.
• Use consistent units.
• Round up slightly if unsure.

Step 3: Enter the Width (W)

Measure the shorter side of the slab and enter it into the Width (W) field.

Make sure:

• The surface is level.
• Measurements are taken accurately from edge to edge.

Step 4: Enter the Thickness (H)

Enter the slab thickness in the Height (H) or Thickness field.

Common slab thickness examples:

• 4 inches – patios & walkways
• 5–6 inches – driveways
• 6+ inches – heavy load areas

If you measured thickness in inches but selected feet as your unit, either convert it manually or switch to inches for easier entry.

Step 5: Click “Calculate”

After entering all dimensions:

• Click the Calculate button.
• The calculator will instantly display:
  • Cubic Feet (ft³)
  • Cubic Yards (yd³)
  • Cubic Meters (m³)

These values represent the total concrete volume required for your slab.

Pro Contractor Tip

Always order 5% to 10% extra concrete to account for:

• Uneven subgrade
• Spillage
• Formwork gaps
• Measurement rounding

Example:
If your result is 4 cubic yards, consider ordering 4.2–4.4 cubic yards.

Units Supported Worldwide

This calculator supports both:

• Imperial Units (Feet, Inches, Yards)
• Metric Units (Meters)

Frequently Asked Questions