Concrete Column Calculator
Welcome to the concrete column calculator - a column version of the concrete calculator. With this tool, you'll find out how to calculate your concrete requirements – to be precise, you'll work out the volume of your column and how much concrete it needs. If you want to use a specific concrete mix ratio, our calculator will give you the volume of cement and aggregate (like sand or gravel) your column needs.
We'll also give you a helpful hand with estimating how many bags of concrete you'll need - so our tool is a great premix concrete bag calculator, too! Please don't wait any longer, give it a go!
What are the components of concrete? What is cement?
What is the difference between concrete and cement? Let's start with the definitions. Concrete is not a standalone material; it's a composite, a mixture of:
- the aggregates - crushed stones, sand, gravel, slag; and,
- the cement paste - comprising of cement and water.
So, what is cement?
Cement is a binder in the form of fine binding powder. It binds the aggregates, as mentioned earlier, together. Cement used for construction is usually lime or calcium silicate based. When you add water to cement, chemical processes cause it to harden.
Sometimes you hear people use the terms concrete and cement interchangeably, but that's not correct.
💡 Cement is one of the ingredients of concrete.
How to figure concrete? How many bags of concrete do I need?
To figure out how much concrete you need to buy, you simply need to multiply the volume required by the density of the concrete mixture. This gives you the weight required. Here are the in-depth steps for columns:
- Find the dimensions of your columns. Provide the diameter or cross-sectional dimensions of your concrete column, as well as its height.
- Determine the number of columns you need.
- Based on this data, our cement calculator will count the overall volume of all of these elements.
Now that we know how to calculate concrete volume, we can go ahead and solve the number of bags you need for your project or the amount of each concrete component (cement, sand, and aggregate) we need. If you chose to purchase premix concrete bags, we can calculate how many concrete bags do we need by following these steps:
- Provide the density of concrete you will use (you will find it on the bag - which is how premix concrete is usually sold). We have provided a common value already. You can also check out how to calculate density in our density calculator.
- Input the weight of one bag of premixed concrete - again, check the bag.
- Account for waste and spillage (usually 5-10%) and voila! Now you know how many bags you truly need.
If you prefer to mix your own concrete, you have to know the mix ratio that you want to follow. Concrete mix ratios determine the strength of the resulting concrete. In this concrete column calculator, we have provided some of the most common concrete mix ratios for you to choose from. In the calculator, you will also see the corresponding strengths of the mixes which you can also check in this table:
After you have chosen the mix ratio you want to use, you have to calculate the volumes of cement, sand, and aggregate that would make up the required concrete volume. We can do this by dividing the volume by the sum of the terms in the ratio. For example, let's say that we want to use a mix ratio of 1:2:4 for a 2 cu yd (1.5 m³) concrete column. Adding the terms of our ratio, 1, 2, and 4, together, we get a sum of 7. By dividing the required volume of 2 cu yd (1.5 m³) by 7, we obtain the cement volume that makes up one part. Following the mix ratio, we can calculate the volumes of sand and gravel required, as shown below:
cement volume = total concrete volume / sum of terms
cement volume = 2 cu yd / (1 + 2 + 4) = 2 cu yd / 7 ≈
0.286 cu yd (0.214 m³)
sand volume = 2 * cement volume = 2 * 0.286 cu yd =
0.572 cu yd (0.429 m³)
gravel volume = 4 * cement volume = 4 * 0.286 cu yd ≈
1.144 cu yd (0.857 m³)
How to use concrete column calculator?
As briefly discussed above, our concrete column calculator can help you find the volume and weight of concrete needed for your concrete column project. To get the most out of our concrete column calculator, here are the steps to follow to find that using our calculator:
- Choose the cross-sectional shape from the drop-down list at the top of our calculator.
- Input the dimensions and height of your column, as well as the quantity of them. By doing this, we will already have calculated the volume of the concrete needed.
- After determining the volume, the next step is to select your preferred concrete mix. You can choose between buying premixed concrete bags and mixing your own concrete.
- By selecting "I'll get premixed concrete bags", you will have to input the desired concrete density to obtain the total weight of concrete needed. Alongside this, you'll have to input the bag size you intend to buy. On the other hand, by selecting "I'll mix my own concrete", you will have to select the mix ratio that you desire.
- Input the assumed wastage of concrete as a percent. Like with other construction materials, we incorporate this contingency in case of spilled materials, material sticking to tools, etc.
- After setting the wastage percentage, our calculator will then provide you with either the total number of premixed concrete bags needed or the volume of each concrete component (depending on what you chose in step 4).
Additionally, our concrete column calculator also works as a good concrete cost estimator when you trigger the Advanced mode of our calculator. In advanced mode, you can input the price of the materials needed to estimate the total material cost of your project, as well as the material cost per column.
An example calculation for premix concrete
So let's say we have two concrete columns, both 1 foot (30.5 cm) in diameter and 4 feet (122 cm) tall. Premixed concrete is usually sold by the cubic yard or cubic meter (the latter is the volume unit we have set by default), but we usually measure construction elements in feet or centimeters. You don't need to worry though, you can input whatever units you like into the calculator and we'll do all the converting for you!
Once we have the above measurements, all that is left to do is to:
- Check if the concrete density from a particular producer is the same as the default value in the concrete column calculator (150 lb/cu ft / 2400 kg/m3). Feel free to change it as needed;
- Use the density to find the total weight of the needed concrete;
- Check the weight of a single bag of cement - our default is 60 lb (25 kg). If you are buying a different bag, change it to the appropriate number;
- Be safe - account for spillage and waste. Experienced contractors usually assume 5-10%.
In our example, we'll use the default measures. We need 6.28 cubic yards (4.8 m3) of cement, and our producer sells cement in bags weighing 60 lb (25 kg) with a density of 150 lb/cu ft (2400 kg/m3). The total weight of concrete that we need is 942.53 lb (427.52 kg). We assume a 5% loss in wastage and spillage. So, there you go, we need 17 bags of cement.
How much does a yard of concrete weigh?
The most straightforward answer to this is: it depends. Precisely, how much a yard of concrete weighs depends on its density.
As we mentioned before, concrete is a mixture of cement, various aggregates (gravel and sand), and water. At times it also contains slag, fly ash, and other admixtures to enhance its properties. Its density depends on several variables: the content of the cement, the amount of water added, the amount (and density) of the aggregate used, and the amount of entrained air.
Common concrete densities are:
- Heavyweight concrete - 5130 to 7020 lbs per cubic yard (190 to 260 lbs/cu ft or 3040 to 4160 kg/m3);
- Standard weight concrete - 3915 lbs per cubic yard (145 lbs per cubic foot or 2300 kg/m3); and
- Lightweight concrete - 2565 to 3132 lbs per cubic yard (95 to 116 lbs per cubic foot or 1520 to 1858 kg/m3).
Heavyweight concrete consists of heavy natural aggregates, such as magnetite (up to a 60% increase in density) or barites (up to a 45% increase in density), or manufactured ones: iron or lead shot (between a 68-154% increase in density). We usually use it for constructing radiation shields (both nuclear and medical). Its properties include high modulus of elasticity, low thermal expansion, and creep deformation.
Lightweight concretes are more porous than standard ones and are manufactured with pumice, scoria, expanded blast-furnace slag, vermiculite, and clinker. It reduces the dead load and increases the speed of building, therefore, decreasing costs. It also has high fire resistance, has better shock and sound absorption, and is characterized by reduced shrinking. There are several types of lightweight concrete. They are commonly used for screeds and walls in buildings, insulation on roofs, or water pipes, precast blocks, and panels.