The decision between B2 and C1 is not just about difficulty level. It depends on why you need the certificate, your timeline, and what a proper diagnostic reveals about your current profile.
A B2 score tells you where you ended up. It does not tell you why, or what to do next. This is the fundamental difference between a level test and a diagnostic assessment.
Most candidates focus on grammar. Examiners focus on task achievement, coherence, and range. Here is how the writing paper is assessed and where marks are most commonly lost.
You will find ranges quoted everywhere: 150 to 200 hours, 3 to 6 months. None of that means anything without knowing your starting level and where your gaps actually sit.
The speaking paper is not an improvised conversation. It has a precise structure and specific assessment criteria. Most candidates fail to prepare for the parts that matter most.
Both are internationally recognised. But IELTS expires after two years, Cambridge does not. The right choice depends on your goal: university, work visa, professional accreditation, or career progression.