Concrete Calculator
Estimate the exact volume and bags of concrete you need for your next project. No complex math, just accurate results.
How to Use This Concrete Estimator?
Welcome to ConcreteCalculator.website. Over the years, we have seen countless homeowners and even contractors struggle with ordering the right amount of concrete. You either order too little and ruin the pour, or order too much and waste money. That is exactly why we built this tool.
Using the calculator above is pretty straightforward:
- Step 1: Select your measurement system. Use Imperial if you measure in feet and inches. Choose Metric if you use meters and centimeters.
- Step 2: Pick the shape of your project. Are you pouring a flat driveway, setting fence posts in a hole or column, or building steps?
- Step 3: Punch in your exact dimensions. For depth and thickness, make sure you measure exactly what your forms are set to.
- Step 4: Hit calculate. The tool will give you the total volume and tell you exactly how many bags of premixed concrete you need to buy from the hardware store.
The Math: How Do You Calculate Concrete Yardage Manually?
Do not want to rely on the tool? It is always good to know the math behind the magic. Here is the standard formula for a basic square or rectangular slab:
Formula: Length in feet multiplied by Width in feet multiplied by Depth in feet equals Total Cubic Feet.
Conversion: Total Cubic Feet divided by 27 equals Total Cubic Yards.
Quick Example: Let us say you are pouring a 10 feet by 10 feet patio, and it needs to be 4 inch thick. First, convert those 4 inches into feet by calculating 4 divided by 12 equals 0.33 feet. Now multiply: 10 times 10 times 0.33 equals 33 cubic feet. Divide 33 by 27, and you get exactly 1.22 cubic yards.
How Much Does a Bag of Concrete Yield?
If you are doing a small DIY project, you are probably buying bags of premixed cement instead of calling a ready mix truck. Here is a quick cheat sheet on bag yields:
| Bag Size | Yields in Cubic Feet | Yields in Cubic Meters |
|---|---|---|
| 80 pound bag | 0.60 cubic feet | 0.017 cubic meters |
| 60 pound bag | 0.45 cubic feet | 0.013 cubic meters |
| 50 pound bag | 0.37 cubic feet | 0.010 cubic meters |
| 25 kilogram bag | 0.39 cubic feet | 0.011 cubic meters |
Frequently Asked Questions
How do you calculate concrete yardage?
To calculate concrete yardage for a standard slab, multiply the length in feet by the width in feet by the depth in feet. Then, divide that total number by 27 because there are 27 cubic feet in one cubic yard.
How many bags of concrete do I need for a 10x10 slab?
For a standard 10x10 feet slab with a 4 inch thickness, you will need about 1.23 cubic yards of concrete. This roughly translates to about fifty six 80 pound bags or seventy four 60 pound bags.
How do I calculate cubic meters of concrete?
To find cubic meters, simply multiply the length in meters by the width in meters and the depth in meters. For example, a 3 meter by 3 meter slab that is 0.1 meters thick requires 0.9 cubic meters of concrete.
Do I need to order extra concrete?
Yes, absolutely. The golden rule in construction is to order 10 percent more than your calculated volume. Forms bow, subgrades are rarely perfectly flat, and spills happen. It is much cheaper to have a little extra than to pay short load fees.