Mechanical keyboards come in many different shapes and sizes. Often the size is given in percent. But what does this percentage mean?
The percentage is to be seen relatively to the size of a default keyboard – now default keyboard is also a matter of interpretation. Technically the default changes from language to language. Different languages have different layouts and thus different amount of keys.
Some sizes are considered impractical by some, but it really depends on your personal needs and is thus a matter of personal taste.
In the following image you can see the default size of an ANSI keyboard and the 60% and 80% equivalents:
The 80% form factor is also often called Tenkeyless or TKL for short. It has basically the same size and layout of a regular 100% keyboard but has the numblock cut off. The indicator LED’s (for scroll and Caps Lock) are often moved to the last column between first and second rows of keys:
75% is quite similar to the 80%, except that the keys are more condensed, some keys are missing all together. The CAPS lock indicator LED is often times beneath the CAPS lock key itself or not present at all.
60% is a very popular keyboard size in the DIY community. Physically the first row with the function keys F1-F12 is missing but they are often mapped to the first row of the keyboard and accessed by a function modifier key. Similarly the cursor keys are mapped to the lower right (Shift, Super, Meta and CTRL) keys and are either accessed by function key or – depending on firmware – by tapping instead of long pressing. This form factor is also often called Poker Sized:
40% is super compact and is missing quite a lot of keys. For keyboards of this size you will almost always want to have two different layers in order to use this keyboard productively. As you can see, the row with the numbers and special characters is missing completely.
Do not be fooled – this is by no means a complete list of all shapes and sizes – there are many, many more, for example num-pads or split keyboards. The above sizes are just the most common ones for which a lot of different hardware is easily available.