You can stay in the UK for the length of your course or research.
You may be allowed to stay an extra 30 days if your total stay in the UK would be no more than 6 months, or no more than 11 months if you’re both:
16 or over
studying an English language course
Your visa will say how long you are allowed to stay in the UK.
If you do not normally need a visa to visit the UK, you can study for up to 6 months without applying in advance. You must see a border officer when you arrive in the UK - do not use the ePassport gates.