We use had better to tell people what we think they should do.
- You had better turn that music down before dad gets angry.
- You had better consult a doctor.
Had better is also used to give advice to ourselves.
- It is seven o’clock. I had better put the meat in the oven.
Had better may suggest a threat. It is not used in polite requests.
- Could you lend me some money? (Request)
- You had better lend me some money. (If you don’t, there will be trouble.) (Order/threat)
Had better refers to the immediate future, but the form is always past. Have better is impossible. After had better we use the infinitive without to.
- It is late – you had better hurry up. (NOT You had better hurried up.)
In British English, better can come before had for emphasis.
- ‘I promise I will pay you back’. ‘You better had’.