Search “Typing Test” in Google and you will get hits for over 1.5 million sites. Start taking some of the tests and discover that nearly each one calculates typing speed a little differently! How do you determine which one calculates your speed correctly, and then how can you compare your results with someone else who took a different test? Testing demands a standard, and therefore the formula for calculating typing speed in WPM (Words Per Minute) needs to be correctly established as a standard for any typing test.

Let’s start by defining the variables of the equation. Ultimately the WPM formula will be expressed in terms of words divided by time in minutes, but the real dilemma is how to define a word. Typing the word “unmanageable” will always be more challenging than typing the word “the,” yet both are defined as one word in the English language. Using a static length of five (the average word length) as the length of a typed “word” is a much better idea. This would make “the” 3/5 of a word and “unmanageable” 12/5 words. We can then mathematically determine that “unmanageable” would count four times as much as “the,” which makes sense because it has four times as many letters. It also would follow that any keyed entry be counted, such as numbers, spaces, punctuation, and any other visible entry.

Five keyed entries seems easy enough to count, but we still have to consider the different ways a user can enter values. A entry can be typed either correctly or incorrectly, and both of these can later be deleted and reentered either correctly or incorrectly any number of times. Luckily we can treat all of these entries the same and calculate a “Gross” or “Raw” typing speed without error deductions. Later we can apply the error deductions to the Raw WPM and calculate the final “Net” typing speed.

The general consensus to calculate net speed from gross speed is to subtract 1 WPM for every error per minute. So if your gross typing speed was 50 words per minute and you had 10 errors during a one minute test, your net typing speed would be 40 WPM. The question is whether all errors or only errors that were left uncorrected should be deducted. The latter is more suitable for the following two reasons. Fixing mistakes not only messes up the typist’s rhythm and likely causes brief pauses, but function keys like the delete key take time to press and do not count as a keyed entry. This means that the time penalty is already built into the process of correcting a mistake. An additional time penalty on top of the inherent time penalty discourages the typist from correcting their mistakes in the first place. While typists should be encouraged to avoid mistakes at all costs, they should also be encouraged and not discouraged from fixing mistakes as they are typing. Errors left in uncorrected are much more devastating and undesirable than errors fixed immediately while typing.

The second reason can be seen in the case of a large number of corrected errors. Let’s say a one minute typing test was taken and the typing speed was calculated as 20 WPM. During the test 20 errors were made but all of them were immediately corrected. If we then deduct the error penalty considering all errors, we calculate the net speed as 0 WPM! An error-free length of text was obviously typed (20 * 5 – 20 = 80 characters to be exact), yet a typing speed of 0 WPM suggests nothing was ever typed. If the mistakes were left uncorrected, obviously one-fifth of a passage typed incorrectly would be a blunder to proofread and 0 WPM would be acceptable since the resulting text would be useless. This proves we should only consider errors left uncorrected with regards to a time deduction.

We now have our equation for calculating typing speed! First calculate the gross speed by adding together every single entry typed, divide by 5, then divide the result by time in minutes. To officially calculate the net typing speed, subtract the error rate (errors left uncorrected per minute) from the gross speed. See attached images for a more mathematical representation of the gross and net speed equations.

Here is an example to clear up any confusion. Say for a 30 second test 100 entries were typed. 95 were typed correctly and 5 were typed incorrectly. Also, two of the correct entries were deleted and re-entered correctly, and three of the incorrect entries were corrected. 100/5 = 20 words were typed in half a minute, giving a gross typing speed of 40 WPM. Two incorrect entries were left uncorrected so the error rate is four errors per minute, giving a final net speed of 40 – 4 = 36 WPM.

Go ahead and try it out! Use this free online typing test which uses the suggested formula above to calculate your typing speed. Hopefully one day there might be more than just one.