"Fluent" is not a level, and that is why the estimates disagree

FSI measures to ILR 3. CEFR describes what you can do. HSK claimed a mapping the CEFR bodies rejected. None of them define fluency, which is why two honest sources can differ by a factor of four.

Aug 8, 2026Kevin Fan

Two sources say Spanish takes 600 hours and 150 hours. Neither is lying. They are answering different questions, and neither said which.

The word doing the damage is fluent, which has no definition in any framework used to assess languages.

What the frameworks actually measure

FSI publishes hours to a defined endpoint: ILR Speaking-3 / Reading-3 — arguing a point in your professional field, reading a newspaper unaided. That is where 600 hours of Spanish goes. It is a high bar and it is precisely specified.

CEFR describes what a learner can do at six levels, A1 to C2, and deliberately publishes no hours at all. Cambridge English publishes guided-learning-hour bands for its own exams, which is where anything resembling a CEFR-to-hours mapping comes from — and those are exam preparation figures, not a claim about the framework.

ACTFL does the same for the US, including for American Sign Language, and likewise states no hours.

Exam bodies certify a syllabus. JLPT publishes what each level requires and explicitly no study hours; the hour figures circulating for N3 and N1 come from schools and blogs. HSK went further and claimed a direct mapping onto CEFR, which the CEFR bodies did not accept and which the German and French associations of Chinese teachers dispute — they put the old HSK 6 nearer B2–C1 than the C2 claimed.

Not one of these frameworks contains the word "fluent" as a defined level.

Where the factor of four comes from

Our own model, Spanish, one hour a day with a tutor:

Target	Hours
A2 — simple everyday exchanges	170
B1 — hold a conversation, handle travel	315
B2 — work, study, argue a point	460
C1 — professional working proficiency	630

Someone writing "fluent in Spanish in 150 hours" who means A2 is not wrong about the hours. Someone writing 600 who means C1 is not wrong either. The disagreement is entirely in the noun.

This is also why the "learn a language in three months" genre survives contact with reality. Three months of serious study genuinely produces something, and calling it fluency is the only step that does not survive scrutiny.

What people usually mean

In practice, when someone says fluent they almost always mean something close to B2: hold a real conversation without visible effort, work in the language, follow a film without subtitles, be wrong occasionally without it mattering.

That is why B2 is our default assumption when a target is unstated, and why every tool here asks for a level rather than for "fluency". A calculator that accepted "fluent" as an input would be inventing the most important number in the answer.

What to do about it

Never accept an hour figure without a level. It is not a number, it is half a number. The most common failure in this entire field is not bad arithmetic; it is a missing noun.

Decide your own target before you compare anything. A2 and C1 are a factor of four apart in effort and are different projects, not different amounts of the same project.

Treat exam levels as syllabus coverage, not proficiency. Passing an exam certifies you handled that exam's content.

The calculator asks for a CEFR level rather than for fluency, and shows the assumption behind every factor. How this is calculated lists all of them, including which are estimates and where the frameworks contradict each other — several do.

Posts resting on the same evidence, picked by shared citations rather than by hand.

What A1 to C2 actually mean, and what they deliberately do not
CEFR describes what you can do at six levels and publishes no study hours, on purpose. The hour figures attached to it come from one exam board, about its own exams. Knowing which is which fixes most confusion in this field.
There is no official ILR-to-CEFR conversion table
Every hours-to-CEFR figure on the internet passes through a conversion that no standards body ever published. Published academic tables disagree by a full level. Here is which reading we take and why it makes our numbers larger.
HSK 6 is not C2, whatever the mapping says
The exam body published a direct HSK-to-CEFR equivalence. The CEFR bodies did not accept it, and the German and French associations of Chinese teachers place the old HSK 6 nearer B2–C1. If you are planning around HSK levels, this is a two-level error.
Why every "hardest language" list disagrees with every other one
Because most of them are ranking a feeling. The one list built from published data has four steps, not a gradient — and it refuses to name a single winner.

Sources

Every figure above, and where it came from. A post that traces other people's unsourced numbers does not get to have any of its own.

Foreign Language Training — US Department of State, Foreign Service Institute
The class-hour bands every estimate on this site starts from, and the definition of the proficiency they lead to (ILR Speaking-3 / Reading-3).
Guided learning hours — Cambridge English
The shape of the curve between CEFR levels. Cambridge publishes cumulative hours per level (A2 180–200, B1 350–400, B2 500–600, C1 700–800, C2 1,000–1,200); our level factors are normalised against the C1 band and every one lands inside its published range.
ILR scale — Wikipedia
That no official ILR-to-CEFR crosswalk exists. Published academic tables place ILR 3/3+ at C1; others put C1 nearer ILR 4. We take the lower reading, which makes our estimates the more conservative of the two.
Zhongwen Shuiping Kaoshi (HSK) — Wikipedia
That Hanban's claimed one-to-one HSK-to-CEFR equivalence was rejected by CEFR bodies and is disputed by the German and French associations of Chinese-language teachers, who place old HSK 6 nearer B2–C1 than C2.
JLPT N1–N5: Summary of Linguistic Competence Required — Japan Foundation / JEES
What each JLPT level certifies. The exam body describes competence, not study hours — the widely circulated hour figures per level come from schools and blogs, not from JLPT itself.
ACTFL Proficiency Guidelines — American Council on the Teaching of Foreign Languages
The proficiency scale ASL is assessed on. Like CEFR and unlike FSI, it describes what a learner can do and deliberately makes no claim about how long getting there takes.