How the numbers are calculated
Words per minute is not a count of words. The standard defines a word as five characters including spaces, so typing 250 characters in a minute is 50 WPM regardless of how many actual words that was. The convention exists because English word lengths vary and a character-based measure is comparable across texts.
Gross WPM counts everything typed; net WPM subtracts errors, and this is the figure worth paying attention to. A test reporting 90 gross with 8 percent accuracy loss describes worse real-world performance than 70 with 99 percent accuracy, because correcting mistakes costs more time than typing slowly would have.
Accuracy is measured differently between tests, which is why scores vary between sites. Some count only uncorrected errors, some count every keystroke that was ever wrong, and some prevent you continuing past a mistake. Comparing scores across different tests is not meaningful; comparing your own scores on the same test over time is.
What typical speeds look like
Average adult typing speed on a full keyboard is around 40 WPM. Professional typists and people whose work is text-heavy commonly reach 65 to 80. Above 100 is fast by any standard, and competitive typists exceed 150, with records above 200 on short passages.
Speed depends heavily on material. Familiar prose is much faster than text with numbers, punctuation, code or unfamiliar proper nouns, so a test using simple common words will report a higher figure than one using realistic text. Code typing is typically far slower than prose for the same person, because symbols require reaches and modifier combinations.
For most work, accuracy and consistency matter more than peak speed. Beyond roughly 60 to 70 WPM, typing is rarely the bottleneck in knowledge work — thinking is — so further gains have diminishing practical value even though they are satisfying to achieve.
Improving, and typing comfortably
The main determinant of progress is whether you look at the keyboard. Touch typing — using all fingers from the home row without looking — is slower at first and has a much higher ceiling, and switching from a self-taught hunt-and-peck method involves a genuine period of getting worse before improving. That dip is the reason most people abandon it.
Practise accuracy first and let speed follow. Typing fast with errors trains the errors, and deliberately typing at around 80 percent of your maximum with near-perfect accuracy produces faster progress than pushing for a personal best each session. Short daily sessions beat long occasional ones.
Ergonomics deserve attention, since typing is a repetitive activity performed for hours. Keep wrists straight and floating rather than resting on a hard edge while typing, forearms roughly parallel to the floor, and the screen at a height that does not require looking down. Take breaks. Persistent pain, numbness or tingling in the hands or wrists is a reason to see a doctor rather than to adjust technique and continue — repetitive strain injuries are much easier to prevent than to resolve.