Open data
CEFR word list
9,985 English words levelled A1 to C2. Each level is the median of three independent sources rather than one authority's opinion. Where the sources disagreed by two steps or more, we say so and leave the word out of our own decisions.
Why a median of three
Word difficulty is less settled than it looks. Comparing our list against Oxford 5000 on the 4,350 words they share, the two agree exactly on 39% and to within one step on 84%. Two careful authorities disagree on the majority of shared words, so treating any single list as ground truth overstates what is known.
Taking the median of three sources does not remove that uncertainty, but it stops any one school of thought from setting the scale, and it makes the uncertainty measurable: we keep the spread between the highest and lowest opinion for every word.
| Source | Words | Agreement with our median |
|---|---|---|
| CEFR-J + Octanove (Tono Laboratory, TUFS) | 8,653 | 81% |
| Israeli Ministry of Education lexical bands | 4,542 | 80% |
| Oxford 5000 | 4,954 | 80% |
No source dominates: the median sits +0.16 of a step from CEFR-J, +0.15 from the Ministry bands and −0.13 from Oxford.
What we do with disagreement
851 words carry a spread of two steps or more. Most are not errors but polysemy: minute is A1 as a unit of time and C1 meaning “negligible”; net is elementary as an object and advanced as net profit. Our list is keyed on spelling and cannot tell those apart, so we exclude disputed words from our own level measurements. Measured effect: including them dropped our text-level accuracy from 66% to 58%.
The list
Sources, licences and what is not here
CEFR-J vocabulary profile, copyright Tono Laboratory, Tokyo University of Foreign Studies. Free for research and commercial use provided the dataset is cited. Octanove Vocabulary Profile C1/C2, CC BY-SA 4.0. Academic Word List (Coxhead, 2000) is used elsewhere in our measurements, not in this list. Ministry of Education lexical bands come from the Israeli English curriculum.
Words marked (Ox) are words where Oxford 5000 was one of the sources consulted. The published level for those words is still our median, not Oxford's value.
604 words are deliberately absent. For those, Oxford 5000 was the only source, so their level would be Oxford's own assignment rather than our derived one. Oxford 5000 is copyright Oxford University Press and we have not established a right to redistribute it, so we do not. We would rather publish a smaller list we can stand behind than a larger one we cannot.
This list is a working artefact of the YAKKI EDU text-levelling work, published so others can check it. If you hold rights in any material here and believe something should not be published, write to [email protected] and we will remove it.
Word levels are estimates for choosing classroom reading material. They are not a proficiency test and not an authority on any learner's vocabulary.