According to this appendix, there are 41,000 Christian denominations in the world. However, most fall under one family which is used to to classify the denominations. In this post, I will focus of the families of denominations (for example Baptist, as opposed to Missionary, Freewill, and Southern Baptist). Below, I have highlighted a few doctrines and ideals that differ from church to church. You will also find a series of graphs below for a visual overview of these differences and similarities. Furthermore, I have provided a few sources for further reading on specific denominations and/or views in case you want to know more (there is way too much to place in this one post).Apocrypha
How many books are there in the Bible? Most Protestants will tell you 66, but those who consider the Apocrypha (or Deuterocanonical books) part of the canon (along with the Old and New Testaments) will give you a number far higher. The Apocrypha contains books which some churches recognize as canon (divinely inspired by God), some churches recognize as peripheral, and others reject. One view of why it should not be included can be found here, and a view a why it should can be found here. This was never mentioned in church when I was growing up, but before decide what you believe, you should probably decide which books you believe in...Trinity
Why do Christians' consider their religion monotheistic? One of my Religion teachers posed this question in class one day. Most Christians will tell you there is God the Father (1 Corinthians 8:6), God the Son (John 10), and God the Holy Spirit (1 John 5:6-8). The Trinity (definition source here) is a doctrine that most denominations hold, which states that there are three divine beings (God the Father, Jesus the Son, and the Holy Spirit) that co-exist in one Godhead. However, not all denominations believe this. Non-Trinitarians believe that there are three separate beings. Some non-trinitarians believe that all three beings are one in purpose, while others demote one or more from the status of God. This is a topic generally brushed over in Church as a given, however, it is one of the major ideas that separates denominations and thus worthy of deep consideration before deciding which you believe. For more on trinitarian views see this list of non-trinitarian views and this article on trinitarian views.Day of Worship
Most people automatically think Sunday when someone mentions the Sabbath, however the Sabbath is actually Saturday, which is a point of contention amongst denominations as well. The question of whether to worship on the true Sabbath (Saturday) or on Sunday is one that may seem minor in the general scheme of things, but could be more important than we think. Verses such as Exodus 31:17 refer to keeping the Sabbath as a sign between God and His children. Some (myself included) believe this sign is the Seal of God mentioned in Revelation. An in depth discussion of this belief can be found here.Salvation
John 3:16 says whoever believes in Jesus is rewarded by eternal life, but some denominations preach heavy emphases on good works are needed, furthermore declaring that salvation can be lost by evil deeds or lack of repentance. The road to salvation should definitely be at the top of the list for topics you should not just take for granted but actually study and affirm for yourself.Predestination
Speaking of salvation, the choice to believe in and accept Jesus belongs to us, or does it? Some churches believe that people are #TeamHeaven or #TeamHell (I couldn't resist doing that) from the start. The root of this belief, for many, is in Jeremiah 1:5. Some cite the 144,000 of Revelation as evidence of predestination, while other churches believe that you alone are responsible for your salvation. Whether you are a believer in predestination or not will probably affect the rest of your views as well.Purgatory & Hell
Purgatory, according to Catholics, is a place where those who believed, but were impure go to be purified before ascending to Heaven. Most other denominations reject the idea of purgatory. Hell on the other hand is something almost all denominations agree on. However there are some (predominately individuals as opposed to defined denominations) that reject the idea of eternal hell (See this wikipedia article on Annihilationism).Diet & Image
Another thing denominations can't agree on is what we should and should not consume. Some denominations preach complete abstinence from alcohol, while others allow real wine during communion. Denominations like the Latter Day Saints (Mormons) believe you should abstain from foods that contain caffeine as well. Some churches suggest vegetarianism. In determining what you believe in regards to diet (among most of the other topics mentioned), I would suggest looking at Jesus—after all He is our perfect example of how to live. (Note some people question whether the word wine in John 2 refers to the alcoholic beverage or grape juice, as Daniel 1:8 suggests consuming wine is to defile one's self).In addition to diet, many denominations disagree on the attire/image of a believer. Some image related customs that are forbidden or frowned upon by certain denominations are as follows: wearing of jewelry, tattoos, women wearing pants, tight and/or revealing clothes, etc.
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*Note: For some sub-denominations could have different views. Also, the information provided is to the best of my knowledge and cited below. If you see a doctrine incorrectly attributed (or not attributed) to a denomination please comment below (or use the contact form on the site) so that it can be corrected as soon as possible. Also, it is easier to view the labels on the x-axis in full screen mode.Sources
Christianity Comparison ChartMore on Trinitarian vs. Non-Trinitarian Views
Comparing Denominations (About.com)
A List of All Denominations
Angelicanism
Pentecostalism
Mormonism
Seventh Day Adventists
Quakers
Jehovah's Witness
Jehovah's Witness & Predestination
Anti-Apocrypha View
Pro-Apocrypha View
Books of the Apocrphya
