Concrete Calculator
The Concrete Calculator estimates the volume and weight of concrete necessary to cover a given area. Purchasing slightly more concrete than the estimated result can reduce the probability of having insufficient concrete.
How to Use
1. Select the shape of your concrete structure
2. Enter the dimensions
3. Adjust concrete density if needed
4. Calculate to get volume and weight
Standard concrete density is approximately 2400 kg/m³
About Concrete
Concrete is a material comprised of a number of coarse aggregates (particulate materials such as sand, gravel, crushed stone, and slag) bonded with cement. Cement is a substance that is used to bind materials, such as aggregate, by adhering to said materials, then hardening over time. While there are many types of cement, Portland cement is the most commonly used cement, and is an ingredient in concrete, mortar, and plasters.
Concrete can be purchased in multiple forms, including in 60 or 80-pound bags, or delivered in large amounts by specialized concrete mixer trucks. Proper mixing is essential for the production of strong, uniform concrete. It involves mixing water, aggregate, cement, and any desired additives. Production of concrete is time-sensitive, and the concrete must be placed before it hardens since it is usually prepared as a viscous fluid. Some concretes are even designed to harden more quickly for applications that require rapid set time. Alternatively, in some factory settings, concrete is mixed into dryer forms to manufacture precast concrete products such as concrete walls.
The process of concrete hardening once it has been placed is called curing, and is a slow process. It typically takes concrete around four weeks to reach over 90% of its final strength, and the strengthening can continue for up to three years. Ensuring that the concrete is damp can increase the strength of the concrete during the early stages of curing. This is achieved through techniques such as spraying concrete slabs with compounds that create a film over the concrete that retains water, as well as ponding, where concrete is submerged in water and wrapped in plastic.
Concrete Calculation Formulas
The calculation of concrete volume depends on the shape of the structure:
Rectangular Slab/Wall:
Volume = Length × Width × Depth
Circular Slab:
Volume = π × Radius² × Depth
Column/Round Footing:
Volume = π × Radius² × Height
Tube with Hollow Center:
Volume = π × (Outer Radius² - Inner Radius²) × Height
Curb and Gutter:
Volume = (Curb Height × Curb Width × Length) + (Gutter Width × Gutter Thickness × Length)
Stairs:
Volume = (Width × Height × Depth / 2) + Sum of Individual Steps
Weight Calculation:
Weight = Volume × Density
Where:
- All dimensions in meters
- Volume in cubic meters (m³)
- Density in kilograms per cubic meter (kg/m³)
- Weight in kilograms (kg)
Types of Concrete
Different types of concrete have different densities and applications:
Standard Concrete: ~2400 kg/m³, used for most construction projects
Lightweight Concrete: 1440-1840 kg/m³, used for reducing structural load
High-Density Concrete: >2600 kg/m³, used for radiation shielding
Reinforced Concrete: Contains steel bars or fibers for increased tensile strength
Prestressed Concrete: Has internal stresses introduced to counteract external loads
Tips for Concrete Projects
For successful concrete projects, consider these tips:
- Always add 5-10% extra concrete to account for spillage, settling, and slight errors in measurement
- Ensure proper site preparation, including compacting the base material
- Use appropriate reinforcement for structural applications
- Plan for proper drainage to prevent water accumulation
- Consider weather conditions when scheduling your concrete pour
- Allow adequate curing time before subjecting concrete to loads