# Concrete Estimator - Tube

Concrete estimator - tube lets you estimate how many bags of cement you need for tube shaped concrete elements - cement is usually sold in bags. If you know the size of the bag, our calculator will help you decide how many bags you need to buy for your project. All you need is a couple of dimensions. Using our concrete calculator you can also figure out overall volume and weight of you concrete tubes. If you would like to estimate the amount of cement you need for differently shaped elements, check our sibling concrete calculators for columns and slabs.

## How to figure out concrete

To figure out how much concrete to buy you simply need to multiply its volume by its density to determine its weight. It is a little more complicated for tubes but you can calculate it easily using our concrete estimator. This is how it's done:

- First, you need to estimate dimensions of your tube shaped elements. Provide the outer and inner diameters, and the hight of the tube.
- Then determine the number of tubes you need.
- Based on this data our concrete - concrete estimator will count the overall volume of all those elements.
- Provide the density of cement you will use (cement is usually sold in bags, therefore you will find this information on the bag). We put in a commonly occurring value, but it can vary. You can also check out how to calculate density.
- Specify the weight of one bag of cement - again check out the bag.
- Account for waste and spillage (5-10% usually) and there you have it - the number of bags you really need.

All dimensions are given in default units. You can change them to any other unit by simply unlocking the field (the padlock button).

## An example calculation

So let's say we have 5 concrete tubes with an inner diameter of 1,3 ft and outer diameter of 1,6 ft, 8 feet high each. Construction elements are usually measured in feet but pre-mixed concrete is usually sold by the cubic yard, therefore our default volume unit is cubic yards. In our example 1,01 cu yd (27,33 cubic feet).

Once we have the above measurements all that is left to do is to:

- check if the density of cement from a particular producer is the same as the default value in our calculator (150 lb/cu ft). Feel free to change it if you need,
- now you know the total weight of the required concrete,
- check the weight of a single bag of cement - our default is 60 lb. If not, again, change it to appropriate weight,
- to be safe, account for spillage and waste. Experienced contractors usually assume 5-10%.

In our example we'll calculate using default measures. We need 1,01 cubic yards of cement, our producer sells cement in bags weighing 60 lb with a 150 lb/cu ft density. Total weight of concrete that we need is 4100,04 lbs. We assume 5% of waste and spillage. Now we know that we need 72 bags of cement.

## How much is a yard of concrete?

A yard of concrete is simply a cubic yard defined as the volume of a cube with sides of 1 yard. A yard has 3 feet or 36 inches in length. Mixed concrete is sold by cubic yards - therefore it is our default unit of volume.