Calculadora de Concreto
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
V = l·w·h; cimento ≈ 310 kg/m³; areia ≈ 0,44 m³/m³; brita ≈ 0,88 m³/m³
About this calculator
The Concrete Calculator is an online tool that estimates the amount of cement, sand, and gravel needed to prepare concrete in a 1:2:3 mix (cement:sand:gravel). This mix is one of the most common in residential and small construction projects, offering good strength and workability. The calculator uses the dimensions of the structure (length, width, height) to calculate the concrete volume, then applies proportion factors for each material. For example, for each cubic meter of concrete, approximately 310 kg of cement, 0.44 m³ of sand, and 0.88 m³ of gravel are required.
How it works: the user enters the measurements of the concrete element (in meters) and the calculator multiplies length x width x height to obtain the total volume. Then it applies the 1:2:3 mix coefficients: cement is calculated by multiplying the volume by 310 kg/m³; sand by 0.44 m³/m³; and gravel by 0.88 m³/m³. The result is displayed in kilograms (cement) and cubic meters (aggregates). Important: these values are approximate and may vary depending on material moisture and cement type.
When to use: ideal for sizing materials for slabs, beams, columns, sidewalks, small foundations, and other structural elements where the 1:2:3 mix is suitable. Also useful for quickly budgeting the amount of concrete needed in renovations or new construction. The calculator prevents waste and shortages, aiding in project planning.
Cautions: the 1:2:3 mix is an empirical mix; for applications requiring controlled strength (such as structural concrete in larger projects), a rational mix design with laboratory tests is recommended. The calculator does not account for losses during transport, pouring, or compaction (typically add 10% to 15% margin). It also does not include water, admixtures, or steel reinforcement. For large volumes, consult an engineer.
Frequently asked questions
Is the 1:2:3 mix suitable for any type of construction?
No. This mix is recommended for small works like sidewalks, slabs, and residential beams. For structures requiring high strength or large volumes, a mix designed by an engineer is necessary.
How do I account for material losses?
It is recommended to add 10% to 15% to the calculated volume to compensate for losses during transport, pouring, and compaction. The calculator does not include this margin automatically.
Does the calculator provide the amount of water?
No. Water is not included because its quantity depends on aggregate moisture and desired workability. Generally, use about 0.5 to 0.6 liters per kg of cement.
Can I use this mix for reinforced concrete?
Yes, for small elements. For reinforced concrete in larger projects, it is essential to follow a structural design with a specific mix and defined characteristic strength (fck).
What does 1:2:3 mix mean?
It means that for each part of cement by volume, two parts of sand and three parts of gravel are used. This proportion is empirical and results in a medium-strength concrete.