One of the things that you are likely to see, wherever you travel in the world and whatever cultures you are mingling in, is playing cards. People all across the globe play games involving the use of cards, with casino ones like poker and blackjack being particularly popular. The different versions of these games, have spread to most places, and people travel to exotic locations to compete, while the comparatively small size of a pack of playing cards also makes them an ideal form of entertainment when travelling. According to an article published on Ladbrokes the size and portability of cards is what most likely led to decks of cards travelling across Europe, primarily in the pockets of soldiers? However, the size of these cards as we know them today has not always been the standard.
In fact, amongst the playing cards commonly in usage now, there are two standard sizes – not one. There is not a great deal of difference between the two, but standard bridge sized cards measure 2.25 x 3.5 inches, while standard poker sized cards are 2.5 x 3.5 inches. These are not the only sizes out there, but they are the two standard sizes used in most of the casino card games. There was never actually a rule put in place for the size of playing cards, but the two sizes referred to above simply became the most popular forms produced, once printing companies in the States began to produce the cards in a mass, mechanised way. Thus it is not so much something that was decided as something which came into being naturally, as a result of mass production, beginning in the 19th Century.
An example of the way this standardisation is not a hard-and-fast rule is the way that certain popular card games – most notably solitaire – employ a different, smaller size of cards. The ones used in this game are usually 1.75 x 2.625 inches, and there are also some variances in the cards used in non-European card games – for example the much longer, thinner cards used in the Chinese game Mah Jong.
Thus there are still games where you will use different sized cards, but there is a misapprehension that poker sizes vary. In fact the single poker size described above is used for all of the variants of poker – and also usually for games like blackjack. However, as outlined before, the standardisation of playing card size happened largely incidentally as the result of mass printing in the 19th century, rather than on purpose. Indeed, although you will almost certainly use standard poker or bridge size cards for your gaming today, many casinos use standard bridge size cards for all their games because they are cheaper.