Have is the base form of the verb that shows possession, relationships, or experiences. Use have with I, you, we, and they in the present, and after modal verbs like can, will, and should. It can be a main verb for ownership or an auxiliary verb to build perfect tenses.

Has is the present simple form used with third-person singular subjects: he, she, it, and singular names. It expresses the same meanings as have, but only with those subjects in the present. It is also the auxiliary form for present perfect with third-person singular.

Had is the past form for all subjects: I, you, he, she, it, we, and they. Use had to talk about possession or experiences in the past, and as the auxiliary verb for the past perfect. Had often signals that something was true before another past time or event.

In the present simple, choose have or has based on the subject, not the object. Use have with I, you, we, and they, and use has with he, she, it, and singular nouns. This form is common for facts, routines, and states like ownership and health.

Subject	Form	Example
I	have	I have a meeting today.
you	have	You have good timing.
he	has	He has a new job.
she	has	She has a question.
it	has	It has a strange smell.
we	have	We have enough time.
they	have	They have two kids.

In the past simple, had is used for every subject. Use it for past possession, past states, and past experiences. If you can replace it with a past time like yesterday or last year, had is usually the correct choice.

Subject	Form	Example
I	had	I had a headache yesterday.
you	had	You had the keys last night.
he	had	He had a busy week.
she	had	She had a dog as a kid.
it	had	It had a flat tire.
we	had	We had dinner early.
they	had	They had a plan.

Use have or has as an auxiliary verb plus a past participle to form the present perfect. This tense connects the past to now, often focusing on results, life experience, or unfinished time periods. Choose have or has by the subject, then use the past participle, not the past simple form.

Rule	Example
Use have with I, you, we, they plus past participle	They have finished the report.
Use has with he, she, it plus past participle	She has moved to London.
Present perfect links past to now and often implies relevance now	I have lost my wallet.
Use present perfect with unfinished time like today, this week, lately	We have worked a lot this week.

Use had as an auxiliary verb plus a past participle to form the past perfect. This tense shows that one past action or state happened before another past moment or event. It helps make the order of past events clear, especially when the sequence matters.

Rule	Example
Use had plus past participle for an earlier past	I had left before she called.
Often paired with another past event in past simple	They had eaten when we arrived.
Use it to explain causes in the past	He was tired because he had worked late.

After modal verbs, use have, not has or had. The modal stays the same for all subjects, and have follows it as the base form. This includes can have, will have, should have, and would have, which can refer to possibility, plans, or past expectations depending on context.

Rule	Example
After a modal, use base form have	She can have a day off.
Modal plus have plus past participle refers to the past	They should have called.
Would have often shows an unreal past result	I would have helped if I had known.

Have can be a main verb that means to possess, but it can also mean to experience or to do an activity. In many expressions, have describes actions like eating, resting, or taking a wash. In these cases, have behaves like a normal verb and follows present and past forms: have, has, had.

Word/Phrase	Definition	Example
have breakfast	eat breakfast	We have breakfast at 7.
have a shower	take a shower	I had a shower after work.
have a break	rest for a short time	She is having a break.
have a good time	enjoy yourself	They had a good time.

Have got is a common alternative to have for possession, especially in British English. In meaning, I have and I have got are usually the same for ownership, but have got is less common for habits and more limited in tense changes. Had got exists but is much less common in everyday speech.

Rule	Example
For possession, have and have got often mean the same	I have a car. / I have got a car.
Have got is not typically used for routines	I have lunch at noon.
Questions and negatives often use have with do, but have got uses have	Do you have a pen? / Have you got a pen?
Have got is especially common in British English	She has got two sisters.