Mark Twain · 1884
About one unknown word every twelve at a 5,000-word vocabulary. Readable, but it wants support — and that band is also where readers most easily fall into flow.
Coverage = the share of words in the text you already know. The research gives two lines: 98% before independent fluent reading is realistic, 95% for the instructional level that needs support (Hu & Nation, 2000). Proper nouns are not counted as unknown — recognising that it is a name is enough; this book has 556 of them.
Comfortable from about 8,000 words, or read it with glosses. 112,141 words in total; at 150 words a minute for a non-native reader, about 12 h 28 min to finish. Average sentence length 18.9 words. Reaching 95% coverage on this book (the floor for readability) takes roughly 10,000 word families.
The opening of Adventures of Huckleberry Finn, word for word. Tap any word you don't know and its meaning here appears beside it — no sign-up, tap as often as you like.
You don’t know about me without you have read a book by the name of The Adventures of Tom Sawyer; but that ain’t no matter. That book was made by Mr. Mark Twain, and he told the truth, mainly. There was things which he stretched, but mainly he told the truth. That is nothing. I never seen anybody but lied one time or another, without it was Aunt Polly, or the widow, or maybe Mary. Aunt Polly—Tom’s Aunt Polly, she is—and Mary, and the Widow Douglas is all told about in that book, which is mostly a true book, with some stretchers, as I said before.
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These are already built, and closest in difficulty to Adventures of Huckleberry Finn.
Ordered by unknown words per 100. Lower reads easier; to step up a level, pick a higher number.
Computed by Readii from the public-domain text (updated 2026-10-21), not estimated by hand. The Readii reading level is our own scale, anchored on unknown-word density; it is not the same system as Lexile or AR and does not convert directly. Unknown words are counted against a frequency list built from a large subtitle corpus, so the bands mean the same thing for any learner of English, whatever your first language. This is difficulty for a non-native reader, not a native-child reading level.