# How To Calculate the Size of a Heating Oil Fuel Tank

When winter comes, the heating oil fuel tank is one of the most valuable resources that you will have around the house, which will provide you with the heat to make it through winter without frostbite and with warm water flowing through the pipes. To know how much heating oil you need to order for the winter, you should learn how to compute the volume of heating oil a heating oil tank can hold. Here’s how.

**Measurement**. Begin by taking the accurate measurements of the heating oil tank. The tanks come in various shapes and sizes, and the shape of the heating tank will largely determine the type of formula that you will use and apply for finding the volume of the heating tank. Use a tape measure to find the dimensions, since these measuring devices are easier to use and can be used for measuring the circumference of rounded tanks.

**Rectangular tanks**. The formula for getting the volume of a tank that is rectangular or square in shape is length multiplied by the width and the height. This means that a tank that is five foot in height, seven foot in length, and three feet in width will have a volume of 105 cubic feet. Keep in mind, however, that when heating oil is purchased, the measurement is usually determined in gallons. Because of this, you will need to convert the measurement to gallons, which can be done by multiplying the cubic feet measurement with 7.48. This means that the tank can hold 785.4 gallons of heating oil.

**Tube tanks**. Another common shape for heating oil tanks is the tube shape, which has rounded tops and bottoms. To calculate the volume that these types of tanks can hold, you will need to multiply the radius squared with pi, which will then be multiplied with the length of the tank. The radius is the length between the circle and the center of the circle. The value for pi is usually found in most calculators, but you can also solve for the calculation on paper by using the first five digits of the pi number, which is 3.1416. Therefore, a tank that is seven feet in height and with a radius of four will have a volume of 301.59 cubic feet. To transform the measurement into gallons, you will need to multiply the measurement with 7.48, resulting in 2255.9 gallons of heating oil.

**Other tank shapes**. In some cases, however, the tanks will have rounded or bulging shapes, in which case you should refer to the manufacturer’s manual for the amount of heating oil in gallons that the tank can hold.

When you purchase the heating oil, it is best if you purchase the oil in large batches to get discounts. You can afford to order large batches by pooling the neighbors to fill in their heating oil tanks at the same time. Through these steps, you should be able to determine how much oil you need to purchase before winter comes.