Difference between How Come and Why

Key difference: ‘How come’ and ‘why’ are two different questions that are asked in the English language. However, the main difference between the two is that ‘how come’ is considered more of an informal question rather than ‘why’ which is considered to be grammatically correct and appropriate.

‘How come’ and ‘why’ are two different questions that are asked in the English language. The two are mostly interchangeable, but they do differ in the manner that they are used. Both can be used to inquire about something, or to ask for an explanation about a situation. However, the main difference between the two is that ‘how come’ is considered more of an informal question rather than ‘why,’ which is considered to be grammatically correct and appropriate.

‘Why’ is an acceptable question in the English language. It is part of the traditional questions, including who, what, where, when, why and how. ‘How come’, on the other hand, falls under the traditional question ‘how’. “How come” is the abbreviated version of “How come it came to be that way?” Many people, in fact do not consider ‘how come’ to be a grammatically acceptable phrase. However, “How come it came to be that way?” is a grammatically correct and accepted question.

‘Why’ is mainly used to seek the reason, cause, or purpose for something. It is more of an authoritative question. It demands an answer, as to ‘why did this happen?’ or ‘why did you or didn’t you do this.’ For example: Why is she at the party? (I want to know the reason.)

As ‘why’ is a standard form of a question, it is used in a standard question form, which means that the subject and verb are inverted. In a question format, the subject follows the verb, such as ‘Why did you say that?’ as opposed to a regular sentence format which is subject verb object, e.g. ‘You did say that.’

Examples:

Why did you behave so badly?
Why did you want to leave the party?
Why did you say that?
Why didn't you do your homework?
Why was she late?
Why did she go?
Why does she have to go?
Why didn't you see the movie with them?
Why did you go to Peru?

‘How come,’ on the other hand, is a more general inquiry about something. It may or may ask or inquire about reasons, causes, or purposes for things. However, it does not demand them. It may not even ask a question, rather it may just be used by the speaker to express disbelief or accusation about the event. For example: How come she is at the party? (I thought she wasn’t going to come.)

Furthermore, as ‘how come’ is not a standard form of a question, it does not need to follow a standard question format. Hence, its subject and verb do not need to be inverted. It usually just follows a standard sentence format of subject – verb – object.

Examples: