The average reading speed of an adult is 200 to 250 words per minute with a high comprehension rate (70-80%). Readers who skim, can read at about 500-800 words per minute, but comprehension drops to about 60%. At the World Championship Speed Reading Competition contestants read as fast as 1,000 to 2,000 words per minute at the expense of comprehension that drops down to 50%-40%. World champion speed reader Anne Jones of England read Harry Potter and the Deathly Hollows in 47 minutes at an astonishing 4,251 words per minute. Who says muggles don’t have magical powers? Harry Potter novels aside, it doesn’t make sense to speed read a great novel; it’s like gulping down a bottle of fine wine. The whole point of reading is to savor the words, the cadence and rhythm of the sentences. But we digress…
Eschewing the seemingly steroid-enhanced performance of speed readers, let us use the 200 per minute as the basis for our calculations. If one were to read the entire second edition of the Oxford English Dictionary (1989), printed in 20 volumes with 21,730 pages and containing over 59 million words, it would take a reader about 205 days (reading 24 hours a day), resulting in a very exhausted, bleary-eyed individual; albeit, one with a very expansive vocabulary. And Ammon Shea, a life-long logophile, did just that in one year and wrote a book about it (Reading the OED: One Man, One Year, 21,730 Pages).
If one were to read the entire printed edition of the Encyclopedia Britannica (2002), consisting of 32 volumes, 33,000 pages, and 44 million words, it would take a reader 153 days. And yes, someone did that too. This time it was stunt journalist A. J. Jacobs who wrote about his read-a-thon titled The Know-It-All: One Man’s Humble Quest to Become the Smartest Person in the World (2004).
If one were to read the soporific U.S. tax code (2012) that contains more than 4 million words, it would take a reader 14 days. The surgeon general has warned that reading that amount of arcane and banal material can be deleterious to your mental health, but will certainly lower your taxes (assuming your comprehension rate stayed high).
If one were to read the King James Bible (the combined word count of the Old and New Testament is about 774,746), it would take 3 days — time worth spending if you want to explore and deepen your faith and spirituality — or lack thereof.
Moving to the more mundane, the average book is about 250 pages long, with about 500 words per page. It will take an average reader about 10.5 hours to read it.
For further reading: Reading the OED: One Man, One Year, 21,730 Pages by Ammon Shea, Perigee (2008).
The Know-It-All: One Man’s Humble Quest to Become the Smartest Person in the World by A. J. Jacobs, Simon & Schuster (2005)