IELTS (International English Language Testing System) is one of the world's most widely accepted English proficiency tests, used for university admissions, immigration, and professional registration. It's scored across four skills — Listening, Reading, Writing, and Speaking — each on a 9-band scale, which are then averaged into a single Overall Band Score.
A band score on its own doesn't always mean much to someone outside the English testing world, which is why many institutions also ask for or report a CEFR (Common European Framework of Reference for Languages) level — the same international scale used to describe ability from A1 (beginner) through C2 (proficient), and the same scale used by Cambridge English Qualifications.
The mapping between IELTS bands and CEFR levels isn't perfectly linear, but broadly: a Band 4.0–5.0 sits at B1, Band 5.5–6.5 at B2, Band 7.0–8.0 at C1, and Band 8.5–9.0 at C2. A Band below 4.0 generally falls below B1. This mapping is published and widely used, which is exactly the data this converter is built on.
If you're applying somewhere that lists a CEFR requirement instead of (or alongside) an IELTS band requirement, this tool gives you a quick way to check whether your result clears that bar before you submit an application.