According to some estimations, there are about two billion Christians in the world, out of a world population of about seven billion, but if you actually look at what the fundamentalist interpretation of the bible says about being a Christian, there are actually a lot less than that, which is not surprising.
How many Christians are there in the world today? I wrote an article recently called Does A Person Need Religion To Be Happy? This talked about a survey that was done to try to find out the happiest country in the world.
Apparently the happiest country in the world is Denmark, and while the Wikipedia figures showed that 80% belonged to a Christian church, the actual figures of the amount of Danish people who even said they believed in God were less than half of that.
I did a search on the religion of Australia, and found that apparently 64% of the people in my country are Christians, which I know for a fact is completely wrong.
I looked up the definition of a real Christian, according to the bible, and found some bible verses which explain what makes someone a Christian.
John 3:3-7 Jesus answered and said to him: "Truly, truly, I say to you, unless one is born again he cannot see the kingdom of God."
4 Nicodemus said to Him, "How can a man be born when he is old? He cannot enter a second time into his mother's womb and be born, can he?"
5 Jesus answered, "Truly, truly, I say to you, unless one is born of water and the Spirit he cannot enter into the kingdom of God.
6 "That which is born of the flesh is flesh, and that which is born of the Spirit is spirit. 7 "Do not be amazed that I said to you, 'You must be born again.'
How Many Christians Are There In The World?
So basically it means that you must not only accept Jesus Christ as your lord and saviour, but you have to be born again, trust Jesus completely to forgive all your sins, and have his spirit dwelling inside of you.
By that definition of the born-again Christian, there are definitely less than a billion Christians in the world. I would go so far as to say that it may not even be the most popular religion, if that is the definition.
In Islam, they don't have such a strict definition of what makes you a Muslim. You must believe in one God, and the teachings of the holy prophet Mohammed.
The third most popular religion (apart from atheism), is Hinduism, which has a very different sort of definition. They generally agree that there is not one right definition of the word God, and they either believe in one God (Brahman), many gods, or that all other gods are part of the one God.
The religion does not have one book, it's an amalgamation of many, many different spiritual cultures that go back to before the first testament of the bible was written.
Buddha was given the title of a God in Hinduism, but the word has a different meaning, as they also believe that Brahman is the one main God who is the universe, and which all other gods are a part of.
Buddhism is the next most popular religion, and they don't believe in God at all, or some believe that God is everything in a similar way to Hinduism. It requires no belief at all, and accepts that there are many different paths to enlightenment.
So how many Christians are there in the world today? If you believe the Jehovah's Witnesses, seven million.