Every IELTS result is a single number from 0 to 9, but that number is not decided the same way for all four skills. Knowing how each one is actually built helps you see exactly what to work on.
Writing and Speaking, four criteria each
Writing is assessed against four official criteria: Task Achievement, Coherence and Cohesion, Lexical Resource, and Grammatical Range and Accuracy. Speaking has its own set of four: Fluency and Coherence, Lexical Resource, Grammatical Range and Accuracy, and Pronunciation. Your overall band for each skill is built from these, not from a single impression of "good English."
That is why two answers that both sound fluent can still land on different bands: one might be strong on vocabulary but repeat the same grammar structure throughout, which caps the Grammatical Range score even if nothing is technically wrong.
Listening and Reading, a conversion table
Listening and Reading work differently: you get a raw score out of 40, which is then converted to a band using an official scoring table. There is no partial credit for style or approach here, an answer is either right or it is not, which makes focused practice on question types especially effective for these two skills.
Practising against the same criteria
ParrotTalk's Writing Checker and Speaking practice score you against these same official criteria, with feedback tied to your own answer, not a generic tip sheet. Reading and Listening use the official Cambridge scoring table for the conversion. Worth being upfront about: an AI-generated estimate can differ from an official result by roughly ±0.5 to 1 band, so treat it as a practice signal to track your progress, not as proof of your level for an application.
The short version: know the criteria, and you know exactly what to fix. All four skills, free, no sign-up.
Your band history across all four skills lives on your dashboard, so you can see which criterion is actually moving.