Know exactly which words you know. Vocabularium turns the words you look up while reading into a vocabulary you actually keep — with a ten-minute baseline test, spaced repetition, and definitions from Webster’s 1828.
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A ten-minute honest test — and yes, some of the words are fakes, so bluffing lowers your score. You'll get your vocabulary size and a map of your knowledge across 12,000 words. The 2,000 words every English speaker shares are assumed; we never quiz you on "the."
Pick any book — a classic from our library or your own epub. Vocabularium computes how much of it you can already read and hands you the exact words standing between you and the story, each with its sentence from the book.
New words enter a spaced-repetition queue tuned to memory research: review just before you'd forget, graduate words to "known," and watch your vocabulary age climb. Ten minutes a day is plenty.
Research on reading puts the comfort threshold at about 98% known words. Below that, a book fights you; above it, the story carries you. Because Vocabularium knows your words — not a grade-level guess — it can compute this number for any book and any reader in your family.
Then it does what no reading level can: prints the missing words, graded from Elementary to Advanced, each with Webster's definition and the very sentence where the word waits for you.
Every great work has an on-ramp. Our ladders measure the vocabulary of each rung — retelling, translation, original — so a reader graduates upward exactly when they're ready, footnotes not required.
Every list is printable, ordered by how much each word matters, and pairs every word with its Webster’s definition and the sentence where it waits for you.
Every word leads with Noah Webster's American Dictionary of 1828 — morally serious, beautifully written, and quoting the same canon your family reads. Modern words get modern definitions; nothing gets a lazy one.
One dashboard for every child. Printable word lists, book-matched reading plans, and progress you can put in a portfolio. Kid-safe definitions, no ads, your data is yours.
Turn any book into a graded vocabulary unit in minutes — with context sentences, answer-ready printables, and defensible level bands built on real frequency data.
Find your true vocabulary size, target the exact frontier of your knowledge, and climb translation ladders until Chapman's Homer reads like it did to Keats.
"Language is the expression of ideas; and if the people of one country cannot preserve an identity of ideas, they cannot retain an identity of language." — Noah Webster, 1828
Ten minutes. A few fake words to keep you honest. A number you'll want to beat.
Take the baseline test