The type of floor you are fitting will determine how it should be measured. As a general rule you need to measure both the longest and the widest points of the room. Multiply the width by the length and that will tell you how much flooring you need. However, keep in mind that when installing vinyl you should take a note of the width and length as these will be required to calculate on the website. When taking measurements it is advisable to allow wastage for cutting and selection, we have an allowance built in to our calculator to accommodate this which can be unticked if not required.