Effective Reading Speed (ERS): Formula & WPM Guide
Anyone can move their eyes across a page at 1,000 words a minute. The real question is: did any of it stick? Effective Reading Speed combines speed and comprehension into one number, so that low comprehension costs you points.
Effective Reading Speed (ERS) is your speed adjusted for understanding: ERS = Raw WPM × (Comprehension Score / 100). A reader at 350 WPM with 85% comprehension achieves 297 ERS, outperforming a skimmer at 600 WPM with 40% comprehension (240 ERS).
Imagine a software engineering team reviewing a critical security architecture document:
- Engineer A whips through the 3,000-word design doc in 3.5 minutes at 850 WPM. When quizzed on the auth protocol and database schema, they score 35%.
- Engineer B sits down for 8 minutes at a steady, focused 375 WPM. When quizzed on the exact same architecture, they score 90%.
Who actually read faster?
A test that only counts speed would rank Engineer A first. But Engineer A skimmed, and missed most of what mattered.
What Is Effective Reading Speed (ERS)?
Effective Reading Speed (ERS) is your words per minute multiplied by your comprehension score. Reading researchers have long combined these two (Jackson & McClelland, 1979; Carver, 1990), and ERS is the name we use for it. It’s a simple, practical score, not a standard research measure.
In 1990, Prof. Ronald P. Carver of the University of Missouri-Kansas City published Reading Rate: A Review of Research and Theory. Carver argued that reading rate and comprehension should be judged together. That is the idea behind ERS.
How Do You Calculate Effective Reading Speed? (The ERS Formula)
To calculate Effective Reading Speed, multiply your raw Words Per Minute (WPM) by your percentage comprehension score divided by 100: ERS = Raw WPM × (Comprehension Score / 100). If you read at 400 WPM and score 75% on a comprehension test, your ERS is 300 words per minute.
Comprehension Score is the percentage of questions you get right without looking back at the text.
Let’s work out the score for our two engineers:
- Engineer A: 850 Raw WPM × (35 / 100) = 297 ERS
- Engineer B: 375 Raw WPM × (90 / 100) = 337 ERS
Engineer B scores 13% higher, despite reading at less than half the speed.
Notice that Engineer A still scores 297, well above the average adult. ERS cuts a skimmer's score, but it can't remove the advantage of extreme speed. That's why our test also asks for at least 75% comprehension before a score can go on the leaderboard.
What Is a Good Effective Reading Speed (ERS) Score?
An average adult scores about 190 ERS (238 WPM at 80% comprehension). There are no published norms for ERS, so this table is worked out from Brysbaert's (2019) reading speeds, assuming comprehension of about 80%.
| Reader | Speed | Comprehension | Effective Speed (ERS) |
|---|---|---|---|
| Below the typical range | Under 175 WPM | 80% | Under 140 ERS |
| Typical adult | 175 – 300 WPM | 80% | 140 – 240 ERS |
| Average adult | 238 WPM | 80% | 190 ERS |
| Faster than most | 300 – 400 WPM | 80% | 240 – 320 ERS |
| Skimming | 600+ WPM | About 40% | Around 240 ERS |
Read the last row with care: a skimmer's 240 ERS is higher than the average adult's 190, but they took in far less. Check your comprehension as well as your ERS, and aim for 75% or higher.
How to Test Your Reading Speed and Comprehension Accurately
To test reading speed and comprehension accurately, read an unread non-fiction passage under a strict timer, then answer passage-dependent factual questions without looking back. Good tests ask about details you can only know from reading the passage.
Get Your ERS in 3 Minutes
Our free test times your reading, asks 4 questions about the passage, and works out your Effective Reading Speed.
Academic References & Primary Sources
- Jackson, M. D., & McClelland, J. L. (1979). Processing determinants of reading speed. Journal of Experimental Psychology: General, 108(2), 151–181.
- Carver, R. P. (1990). Reading Rate: A Review of Research and Theory. Academic Press, San Diego, CA. ERIC:ED347525
- Carver, R. P. (1992). Reading rate: Theory, research, and practical implications. Journal of Reading, 36(2), 84–95. ERIC:EJ452755
- Rayner, K., Schotter, E. R., Masson, M. E., Potter, M. C., & Treiman, R. (2016). So much to read, so little time: How do we read, and can speed reading help? Psychological Science in the Public Interest, 17(1), 4–34. doi:10.1177/1529100615623267
- Brysbaert, M. (2019). How many words do we read per minute? A review and meta-analysis of reading rate. Journal of Memory and Language, 109, 104047. doi:10.1016/j.jml.2019.104047
Frequently Asked Questions
What is Effective Reading Speed (ERS)?▼
Effective Reading Speed (ERS) is your reading speed adjusted for how much you understood: ERS = WPM × (comprehension % / 100). The idea of combining speed and comprehension is an old one in reading research (for example Jackson & McClelland, 1979; Carver, 1990). ERS is the name SpeedReadTest uses for it.
How do you calculate Effective Reading Speed?▼
To calculate Effective Reading Speed, divide your total words read by time in seconds, multiply by 60 to find raw WPM, then multiply by your comprehension percentage divided by 100. For instance, 350 WPM at 80% comprehension equals 280 ERS.
What is a good Effective Reading Speed (ERS) score?▼
There are no published norms for this exact score, so treat these as rough guides. An adult reading at the average 238 WPM with 80% comprehension scores about 190 ERS. Most adults read at 175–300 WPM (Brysbaert, 2019), which at 80% comprehension is about 140–240 ERS. Above 300 ERS is unusual on a fair test.
Why is raw WPM alone a misleading metric?▼
WPM only measures how quickly you got to the end. If you read at 800 WPM but answer 30% of the questions correctly, you skimmed. Multiplying by comprehension cuts that score to 240, but a very fast skim can still beat a careful reader, so comprehension needs its own check too. Our test asks for at least 75% before a score can go on the leaderboard.