A4 vs A5 Size Paper
May be you have no interest in knowing some exciting facts about international paper sizes as you do not need to make use of different paper sizes every now and then. Still it makes sense to know the difference between standard paper sizes that have been cleverly designed according to ISO 216 and ISO 269, so that there is no confusion in whichever part of the world you are in. Though A4 is the most popular size of paper and finds maximum uses (in offices and official documents), A5 is also important and you better know the differences between A4 and A5.
All paper sizes defined in ISO 216 (there are two series namely A, B) and ISO 269 ( series C) are in an aspect ratio of one is to square root 2, which implies that every next size in the series can be obtained by halving the earlier size along the shorter side, and the aspect ratio is not changed. Every series begins with 0 and goes up to 10. The number tells us how many times the paper has been halved. We begin with A0 and halve it along the shorter side (length halved) to get A1, and so on. A4 is the most commonly used paper size, and it is used for letters and other official documents. The actual size of A4 is 210x297mm or 8.27×11.69inch and A5 is 148x210mm. ISO is a standard that has been accepted by nearly all countries of the world except US and Canada where letter size paper is the standard, though there is very little difference in size with A4.
When A4 is folded along its shorter side, we get A5 size paper which is 148x210mm or 5.83×8.27 inches. A4 is found to be large for hand written letters, and a lot of paper gets wasted while A5 is also not fit as it is too short for hand written letters. However, A4 is the standard letter size, while A5 is considered fit for tabloids. A4 turns into A5 which is good fit into a C5 envelope.