How Long Does It Take To Be An American Citizen?

It depends upon the situation you are in to get the citizenship. Either you are there as a spouse or you are there on work.

For example if your father have citizenship of America you might take 4 years to get the American citizenship. For more details, visit the following American Visa Website.
American Visas

When I got mine, before the terrorism thing-e, there are five preferences. Parents to children, sister to sister, or brother to brother, boy girlfriend relationship, like that.

It it's parent to children usually the waiting period is 5 years after they are already here or after they applied for it.

But of course, to make sure visit the immigration website - you can even download an application there.

In normal circumstances, an immigrant  should be a permanent resident for five years to be eligible for  citizenship. If you are married to a US citizen, then it is three  years of permanent residency.It is that you have to be in marriage to  a U.S citizen and should be living with that U.S citizen for the past  3 three years of your permanent residency for the criteria to be  applicable to you.      Current regulations do allow a person  to start the application process ninety days before they fulfill  their residency requirement.

Assuming that you already are a permanent resident  in U.S. And have established residency in the United States for the required amount of time, the actual US citizenship application process can take between six months to year, or even more. To begin the citizenship process, you will need to file USCIS form N-400. Processing of this form can take a little as six months or more than a year. Any mistakes on your form can delay the process considerably, so it is important to fill out the application for citizenship (N-400) as accurately and as fully as possible.