Concrete Calculator

What Is Concrete and Why Does It Matter?

Concrete is a composite material made from Portland cement, water, sand, and gravel or crushed stone aggregate. When mixed properly, these ingredients form a paste that hardens over time into one of the most durable building materials available. From residential driveways and patios to commercial foundations and retaining walls, concrete is the backbone of modern construction across Indiana.

Understanding how much concrete you need before starting a project saves money, reduces waste, and ensures you have enough material to finish the job without costly delays. Whether you are pouring a small sidewalk section or a full garage slab, accurate calculations are essential for a successful outcome.

How to Calculate Concrete Volume

Calculating concrete volume is straightforward. Measure the length and width of your project area in feet, then determine the depth (thickness) in inches. The formula converts these measurements into cubic yards, which is how ready-mix concrete is sold in Indiana:

Cubic Yards = (Length ft x Width ft x (Depth in / 12)) / 27

For example, a 20-foot by 10-foot patio slab at 4 inches thick needs: (20 x 10 x 0.333) / 27 = 2.47 cubic yards. Always order 5 to 10 percent more than your calculation to account for uneven subgrade, spillage, and form irregularities. Running short mid-pour creates cold joints that weaken the slab.

If you are mixing bags by hand instead of ordering a ready-mix truck, the calculator above converts cubic yards into the number of 60-pound or 80-pound bags required. For projects larger than 2 cubic yards, a ready-mix delivery is almost always more cost-effective and produces a more consistent result.

Concrete Pricing in Indiana

Ready-mix concrete in Indiana typically costs between $130 and $170 per cubic yard as of 2025, depending on the mix design, delivery distance, and supplier. Standard 3,000 PSI residential mix falls on the lower end, while higher-strength 4,000 PSI mixes for driveways and garage floors cost more. Short-load fees apply when ordering less than a full truck (usually 8-10 yards), adding $50 to $100 to smaller orders. Delivery fees vary by supplier and distance from the batch plant. Central Indiana homeowners in areas like Indianapolis, Carmel, and Greenwood generally see prices in the $140 to $160 range for standard residential pours.

When Do You Need a Permit for Concrete Work in Indiana?

Permit requirements for concrete projects vary by municipality across Indiana, but there are common patterns. In most jurisdictions, you will need a building permit for any new concrete slab that serves as a structural element, including garage floors, building foundations, and basement slabs. Driveways and patios may require permits depending on size, setback requirements, and whether they affect drainage on your property or neighboring lots.

Retaining walls over 4 feet in height almost always require a permit and may need engineered drawings. Sidewalk replacements in the public right-of-way often require a right-of-way permit. Small repair patches and decorative stepping stones generally do not require permits, but check with your local building department to be sure. Failing to pull a required permit can result in fines, forced removal, or complications when selling your home.

Tips for a Successful Concrete Pour

Proper preparation is just as important as getting the right amount of concrete. Compact the subgrade thoroughly and add a 4-inch gravel base for drainage. Set forms with a slight slope (1/8 inch per foot minimum) to direct water away from structures. In Indiana's freeze-thaw climate, air-entrained concrete is recommended for all exterior flatwork to resist cracking from ice expansion. Schedule pours when temperatures will stay above 50 degrees Fahrenheit for at least 48 hours after placement. Cure the slab by keeping it moist for at least 7 days, either with wet burlap, curing compound, or plastic sheeting. Proper curing can increase the final strength of your concrete by 50 percent compared to letting it dry out too quickly.