Amazon recently introduced a feature on its site called “Text Stats,” which lets you see things like the grade level, word count, and other statistics for books in its “Search Inside the Book” (SITB) program.
Here are a several Bible translations plotted by the total number of words in the translation compared to the number of words per sentence:

The NAB includes the Apocrypha. We couldn’t find stats on Amazon for the RSV without the Apocrypha or the TNIV.
Here’s the raw data if you want to crunch your own numbers. Since Amazon is scanning books and using optical-character recognition, caveats apply: the data may be inaccurate or even misleading. Use with care.
| Version | Complex Words | Syllables per Word | Words per Sentence | Fog | Flesch | Flesh-Kincaid | Characters | Words | Sentences | ISBN |
|---|---|---|---|---|---|---|---|---|---|---|
| AMP | 9% | 1.4 | 25.1 | 13.5 | 62.9 | 10.7 | 5,322,088 | 945,454 | 37,608 | 0310951410 |
| CEV | 7% | 1.4 | 12.8 | 7.9 | 77.6 | 5.6 | 4,337,680 | 757,814 | 59,284 | 0399153853 |
| ESV | 7% | 1.3 | 22.1 | 11.7 | 70.6 | 8.9 | 4,366,324 | 804,566 | 36,457 | 1581345968 |
| HCSB | 8% | 1.4 | 18.7 | 10.7 | 70.9 | 8.0 | 4,264,305 | 758,756 | 40,551 | 1586401734 |
| KJV | 6% | 1.3 | 22.5 | 11.3 | 71.1 | 8.9 | 4,613,643 | 805,649 | 35,742 | 0785202684 |
| MSG | 8% | 1.4 | 13.0 | 8.4 | 73.9 | 6.2 | 4,408,142 | 775,020 | 59,706 | 1600060226 |
| NAB | 9% | 1.4 | 15.9 | 10.1 | 70.4 | 7.4 | 6,891,503 | 1,159,572 | 73,146 | 0840713665 |
| NASB | 7% | 1.3 | 23.6 | 12.1 | 69.8 | 9.4 | 4,251,392 | 784,841 | 33,224 | 0310917255 |
| NIRV | 5% | 1.3 | 9.1 | 5.8 | 86.3 | 3.5 | 4,685,073 | 873,450 | 95,999 | 031092653X |
| NIV | 7% | 1.4 | 18.6 | 10.3 | 73.1 | 7.7 | 4,143,219 | 741,065 | 39,873 | 0310902711 |
| NJB | 8% | 1.4 | 21.1 | 11.7 | 66.9 | 9.2 | 4,692,151 | 836,778 | 39,738 | 0385493207 |
| NKJV | 7% | 1.4 | 23.1 | 12.2 | 68.8 | 9.4 | 4,387,700 | 803,611 | 34,837 | 0785200304 |
| NLT | 8% | 1.4 | 14.8 | 9.1 | 73.7 | 6.7 | 4,457,847 | 782,244 | 52,787 | 0842384898 |
| NRSV | 8% | 1.4 | 22.8 | 12.2 | 68.1 | 9.4 | 4,216,427 | 780,660 | 34,213 | 0521507790 |
Inspired by Steven Johnston.
Update: Per Better Bibles Blog, we added the CEV and changed the ISBN used for the HCSB, which puts its stats closer to the NIV’s.

Many thanks to the ESV Bible Blog for joining the conversation on reading level statistics. They have posted a chart representing reading level statistics from Amazon. I am unsurprised to see that the King James Version has less complex…
Trackback by Reading Levels at Amazon — November 17, 2007 @ 7:50 am