Mary Shelley · 1818
More than one unknown word in eight. Not unreadable — just not readable the look-every-word-up way. Start by accepting you will not follow every sentence.
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 254 of them.
Advanced — read it with glosses. 75,109 words in total; at 150 words a minute for a non-native reader, about 8 h 21 min to finish. Average sentence length 22.4 words — on the long side, so the load comes from sentence structure as much as from vocabulary. Reaching 95% coverage on this book (the floor for readability) takes roughly 14,750 word families.
The opening of Frankenstein, 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 will rejoice to hear that no disaster has accompanied the commencement of an enterprise which you have regarded with such evil forebodings. I arrived here yesterday, and my first task is to assure my dear sister of my welfare and increasing confidence in the success of my undertaking.
I am already far north of London, and as I walk in the streets of Petersburgh, I feel a cold northern breeze play upon my cheeks, which braces my nerves and fills me with delight. Do you understand this feeling? This breeze, which has travelled from the regions towards which I am advancing, gives me a foretaste of those icy climes. Inspirited by this wind of promise, my daydreams become more fervent and vivid. I try in vain to be persuaded that the pole is the seat of frost and desolation; it ever presents itself to my imagination as the region of beauty and delight.
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These are already built, and closest in difficulty to Frankenstein.
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.