Many people ask this question, many people answer it. But there are still some doubts. So, let’s clarify this. Many people think that size doesn’t matter – the technique is the key. Ohh… that’s just terribly wrong. Size does matter, because it must be easy on the eye and we must feel confident and comfortable when operating with it.

Size and shape of credit cards was specified by ISO ((International Organization for Standardization))/IEC ((International Electrotechnical Commission)) 7810 as ID-1 format. ID-1 defines not only the properties of payment cards, but also passports, driving licenses, identity cards and it’s also a common format for business cards. Detailed characteristics of ID-1 (as credit cards) are described within a few other standards:

• ISO/IEC 7813 defines additional characteristics like thickness and rounded corners radius, embossed characters
• ISO/IEC 7811 defines techniques for recording data and magnetic stripe formats
• ISO/IEC 7816 defines everything that comes with embedded chip

That’s not all – ISO/IEC also specifies physical characteristics that every ID-1 must fulfill, such as durability, bending stiffness, toxicity, flammability, resistance to heat.

The card size is defined as:

• 85.60 mm (3.370 in) width
• 53.98 mm (2.125 in) height

And here comes the fun or disappointing part (depending on the point of view).
The width to height proportion equals ~1,586, which is ~0,032 less than the golden ratio ~1,618. Not so perfect after all…

Wojtek

Wojtek is a pretty tall guy (2 meters / 6.56 feet) and doesn't talk much, so sometimes people think he looks down on them not only literally. But if you spend some time with him, you'll find out he's a really friendly person with a great sense of humor. Though still, at work (besides joking) he usually writes his code, sitting in the corner of the room with headphones on.