Concrete Calculator
The Concrete Calculator estimates the volume (cubic feet, cubic yards, cubic meters), ready-mix concrete bags, weight of the concrete (lb/kg) and cement bags along with sand, gravel and steel for your projects.
Slabs or Square Footings
Tip: Add 5–10% extra material to account for waste and spills during pouring.
Enter your square/rectangular footing details and hit calculate to generate estimates!
Round Footings, Hole, Column
Tip: Add 5–10% extra material to account for waste and spills during pouring.
Enter your round footing details and hit calculate to generate estimates!
Hollow Tube and Circular Slab
Tip: For a tube, inner diameter must be less than outer diameter. Add 5–10% waste.
Enter dimensions and hit Calculate!
Curb and Gutter Barrier
Tip: Standard curb height is 6", curb width 8", gutter width 24", and flag thickness 6". Add 5–10% for waste.
Enter dimensions and hit Calculate!
Stairs
Tip: Standard rise is 7" and tread is 11". Formula: V = Width × Tread × Rise × N×(N+1)/2. Add 5–10% for waste.
Enter stair dimensions and hit Calculate!
Planning a construction project? Before starting any concrete project, it is important to calculate the right amount of concrete required to cover a given area. Miscalculations can lead to delays, extra costs, or material shortages.
This concrete calculator is designed to provide quick and accurate estimates of volume (in cubic feet, cubic yards, or cubic meters), weight (in kg/lb), and the number of bags for your project. This free online tool helps builders, contractors, and site engineers determine quantities for slabs, columns, footings, and foundations with precision.
How to Use the Concrete Calculator?
To get started, enter your project dimensions using your preferred unit system. The calculator supports:
- Feet
- Inches
- Yards
- Meters
- Centimeters
Depending on your project type, enter the required dimensions such as length, width, depth, height, diameter, thickness, stair rise, run, or platform depth.
After entering the measurements, choose whether you want Ready-Mix Concrete results or Material Estimations.
Ready-Mix Concrete Option
If you check the Ready Mix Concrete box, the calculator will estimate concrete volume and weight across multiple units:
- Cubic feet (ft³)
- Cubic yards (yd³)
- Cubic meters (m³)
- Cubic inches (in³)
- Cubic centimeters (cm³)
- Pounds (lb)
- Kilograms (kg)
- Ton
- Ounce (oz)
- Concrete density
- Density units (kg/m³ or lbs/ft³)
- Waste % (5–10%)
This option is ideal for ordering ready-mix concrete from a supplier or concrete truck delivery service.
Material Estimation Option
If you leave the Ready-Mix Concrete box unchecked, the calculator will estimate construction materials individually:
- Cement bags
- Sand
- Gravel / Aggregate
Users can also customize cement bag size, unit system (kg or lb), and waste allowance percentage. This mode is useful for DIY concrete mixing, residential projects, patios, sidewalks, driveways, foundations, and small construction jobs.
Instant Multi-Unit Results
The calculator instantly converts and displays results in cubic feet, cubic yards, and cubic meters — helping users compare measurements easily for both residential and commercial concrete projects.
How Much Concrete Do I Need?
To determine how much concrete you need, use our calculator or calculate the total concrete volume by multiplying length × width × depth (thickness) in feet to get cubic feet, then dividing by 27 to find cubic yards.
Quick Reference
| Slab Thickness | Coverage per Cubic Yard |
|---|---|
| 4 inches | ~81 sq ft |
| 5 inches | ~65 sq ft |
| 6 inches | ~54 sq ft |
Always add 5% to 10% for waste and uneven ground as a safety margin.
Concrete Density Options
This concrete volume calculator supports all kinds of densities — choose based on your concrete needs:
Common Concrete Projects & What You Need
| Project | Recommended Thickness | Typical Area | Estimated Concrete |
|---|---|---|---|
| Sidewalk | 4 inches | 3 ft × 20 ft | ~0.74 cu yd |
| Patio | 4 inches | 12 ft × 16 ft | ~2.37 cu yd |
| Driveway | 4–6 inches | 10 ft × 20 ft | ~3.7–5.6 cu yd |
| Garage Floor | 4–6 inches | 20 ft × 20 ft | ~7.4–11.1 cu yd |
| Fence Post | 10″ dia × 3 ft deep | Per post | ~0.14 cu yd/post |
How Many Bags of Concrete Do I Need?
The number of concrete bags required depends on the total volume of your project in cubic feet or cubic yards. To estimate bags, divide your total volume by the yield of one bag.
Most residential projects like patios, walkways, and slabs use this method for quick calculation.
Concrete Bag Cost
A standard 60 lb to 80 lb bag of pre-mixed concrete generally costs between $4 to $9, depending on the brand, location, and market conditions. Specialty mixes like fast-setting or high-strength concrete usually cost more.
Concrete Slab Cost Calculator
Concrete slabs cost an average of $7 to $18 per square foot installed, or roughly $600–$1,500+ for a 10×10 slab, depending on thickness, reinforcement, and location.
| Cost Component | Rate |
|---|---|
| Concrete material | $140–$200 per cu yd |
| Labor cost | $5–$8 per sq ft |
| Standard installed (4″) | $7–$18 per sq ft |
| 10×10 slab estimate | $600–$1,500+ |
A 6-inch slab requires 50% more concrete than a 4-inch slab.
Concrete vs Cement
These terms are often confused, but they have very different meanings.
Cement
A fine powder made from limestone and clay that acts as the binding agent. It is an ingredient, not a finished product. Commonly calculated at a ratio of 1:2:4. A standard 50kg bag is often used.
Concrete
The final material — a mixture of cement (typically 10–15%), water, sand, and coarse aggregate like gravel or crushed stone. Think of cement as flour — concrete is the baked bread. Learn more about different types of concrete and their specific uses in construction.
When water is added, a chemical process called hydration begins, turning concrete into a strong, rock-like material.
How to Make Concrete?
Mix 1 part cement, 2 parts sand, and 3 parts gravel (or 4 parts all-in-one ballast) by volume. Gradually add water while mixing until a workable, plastic consistency is achieved.
Concrete should be placed within 90 minutes of mixing to maintain proper workability and ensure optimal strength development.