## One-dollar bill and origami

Making dollar bill origami models is very popular these days. If you search the Internet, you will easily find thousands of origami models made out of a dollar bill. You can also search the Internet to find similar models made out of European euro or Japanese yen banknotes and you will most certainly find some. But to be honest, a dollar bill is by far the most used banknote in origami.

Why is it so?

Well, I have heard many theories, but the most coherent one, at least for me, was the one based on a banknote size.

Let me show you why?

## A4 paper format

Using money as a working material for origami design is not that smart if you are not positively sure that you know what you are doing. The “Trial and error” approach is not a good idea if you use real money. A wiser procedure would be to develop and initially fold a model using plain paper. Only then, when the complete plan of action is known, you should try to fold a final model using a real banknote.

And here comes the problem. Where are you going to find a paper that, at least roughly, matches banknote size and dimension?

Believe me, a paper of appropriate size is hard to find, not to say impossible. So, the only possible alternative is to cut the fitting size out of the larger paper.

In this respect, a dollar bill is a primary choice for origami enthusiasts, because it is possible to cut dollar size paper out of the A4 paper with only one straight cut.

You see, A4 paper format is the most widely used paper format in the world. You can come across it in almost any office, school or a university.

The exact size of A4 paper is 297×210 mm. But what is especially interesting for this particular purpose is the fact that if we cut a simple square out of it, the remainder that is left has the almost the same dimensions as a dollar bill. When I say “almost the same”, I do not talk about the actual size of a banknote, but rather about the ratio between height and width (look at figure 2).

## Banknote Sizes

The banknotes of various other world currencies differ significantly among each other. Not only in that the different currencies are not of the same size, but different denominations of the same currency differ, too.

Height/width ratios of all banknotes are shown in the last column. Please, notice the difference. Not only that banknotes are different in size, but the height/weight ratio is different too.
Now, we can compare the height/width ratios of various banknotes with the height/width ratio of an A4 paper remainder (figure 3). It is obvious that only a Dollar bill is similar to the A4 paper remainder. Other banknotes are not even close.

Sources:

https://www.ecb.europa.eu/pub/pdf/other/euroleafleten.pdf?985a0982cc26b6299d95ca2da9b7dc1d

https://www.boj.or.jp/en/announcements/education/oshiete/money/c15.htm/

https://www.bankofengland.co.uk/banknotes/current-banknotes

## Final word

Therefore, I hope I have managed to convince you how easy it is to make a dummy (plain paper) banknote that has the same height/width ratio as a dollar bill. For all other currencies, the process is much harder since it involves measurement. That is probably the key reason behind a dollar bill popularity in the origami world.

Nevertheless, the whole theory is not without a few shortcomings, among which I would like to highlight one. You see, a dollar is an American currency, and one could expect that most origami models made from dollar bills would come from the USA. Most likely, it is so, but there is a small problem. In the USA, ISO A4 paper format is not in use. In the USA the ANSI/ASME Y14.1 standard is an official standard that defines paper sizes. According to ANSI standard, a paper size most similar to the ISO A4 paper format is a Letter format (297,4×215,9 mm or 8,50×11,0 in).

If we apply the same procedure, meaning if we cut a square out of the Letter paper, the remainder would have the height/width ratio of 0,3775. This ratio is reasonably similar to the dollar height/width ratio but still not good enough. At least if compared with height/width ratio of an A4 paper remainder.

Is this a problem? I do not know. It could be. Someone could argue that the whole theory behind dollar bill popularity based on A4 paper dimensions is circumstantial. To some extent, I can agree. But then again, this is just an idea, a theory I find interesting and worth mentioning.

After all, if someone wants to make an origami model out of some world currency banknote, he or she can do it. It is hard to believe that the size of a banknote is going to be the major obstacle.

I hope you agree.