Concrete Calculator
Estimate concrete volume in cubic yards for slabs and pads.
Use decimals when needed. This estimate updates live and is safe to tweak before you buy materials.
Concrete Buying Guide
This guide helps you turn your concrete calculator result into a cleaner purchase plan. Use it when you want fewer return trips, better waste assumptions, and a more realistic cart.
Step 1: Measure depth accurately
The depth of your slab or footing dictates the volume. Measure depth in several places, as the ground is rarely perfectly level. Use the thickest point for your estimate.
Step 2: Add a generous margin
Running out of concrete during a pour is a disaster. Always add 10% extra to your calculated volume to account for uneven subgrades and spillage.
Step 3: Choose bags vs. a truck
If your project needs more than 1 cubic yard (about 45 of the 80lb bags), it is usually cheaper and much easier on your back to order a ready-mix truck.
Recommended for this job
Commonly paired tools and accessories
These are the practical extras people often forget until the last minute, especially when turning a rough estimate into a real purchase list.
Concrete floatWhy this helps: Common add-on that reduces last-minute store runs once the estimate is final.
Rebar chairsWhy this helps: Common add-on that reduces last-minute store runs once the estimate is final.
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Concrete cost planning rule of thumb
Beyond the concrete itself, budget for wooden forms, stakes, rebar or wire mesh for reinforcement, and curing compound.
Understanding the Math
Formula: The basic formula for Concrete Calculator typically involves calculating the total area or volume (Length × Width × Depth) and dividing by the coverage of a single unit or package, then adding a waste factor (usually 10%).
Example: For example, if you have a 10x10 area and your material covers 10 square feet per unit, you need 10 units. With a 10% waste factor, you should purchase 11 units to ensure you don't run short.
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Concrete Calculator FAQ
How much extra concrete should I order?
Most projects add 5-10% for spillage and uneven base.
Can I mix by hand?
Small jobs can, but larger pours are usually easier with ready-mix delivery.
How much does a yard of concrete weigh?
One cubic yard of concrete weighs approximately 4,000 pounds (about 2 tons).
Do I need rebar or wire mesh?
For driveways and heavy-load areas, rebar or wire mesh adds tensile strength and helps prevent cracking.