WPM ⇄ CPM converter

Real words vary in length, so counting them directly would make every test incomparable. The fix, settled decades ago, is to define a word as five characters — spaces and punctuation included. Type 300 characters in a minute and you typed 60 standardized words, whatever the actual sentences were. That convention is the only reason a number like average typing speed means the same thing on two different keyboards.

So the conversion is exact, both ways: multiply WPM by 5 to get CPM, divide CPM by 5 to get WPM. The choice is mostly about what you want to see. WPM is the human-scale number people quote; CPM is finer-grained and reacts faster, which is why it reads better on a live speedometer where a single burst should move the needle.

CPM also earns its keep where the five-character rule breaks down. In CJK input — Chinese, Japanese, Korean — one keystroke through an IME can commit a whole character or word, so WPM understates the work and a raw characters-per-minute count is closer to the truth. The same goes for code and numbers, where five-character "words" are a fiction. If you want a clean read of your own rate rather than a debate about units, the simplest move is a short typing test that reports both side by side.