When bitcoin was created, its inventors expected it to be expensive at some point in the future. As it turned out, they were correct, as the price for the bitcoin grew over the years and currently, one bitcoin is worth approximately $4600 (Aug 2017). Because of the price fluctuations and a high price that the cryptocurrency would get at some point, bitcoin creators and users developed a metric system of units that bitcoin could be broken into. Similarly to the classic currencies, Bitcoin too has its own system of denominations. Thus, it is easier to buy Bitcoin, as people could afford to purchase a smaller part of a Bitcoin, instead of buying a whole one. One of the main reasons behind the higher price of the Bitcoin is that in contrast to regular currencies, there is a fixed limit of number of bitcoins that is 21.000.000.
Types of Bitcoin units:
As the majority of world's currencies, bitcoin uses the decimal denomination system. There are different systems of denominations of the bitcoin, some of them, have 6 units, some 8 and some even 10. All bitcoin denomination systems have 4 common units: Bitcoin (BTC or sometimes XBT), MilliBitcoin (mBTC) - one thousandth of a Bitcoin, MicroBitcoin (μBTC) - one millionth of a Bitcoin and Satoshi. The satoshi is the smallest Bitcoin unit which was named after the alias of the supposed creator (or group of creators) of the Bitcoin. One satoshi is a hundred millionth of a single bitcoin (0.00000001 BTC).
It is commonly thought that there are three types of bitcoin denominations systems: Bitcoin (Bitcoin and its main denominations such as mBTC and μBTC are mostly used for major financial operations), Bitcoin block reward (for bitcoin miners) and satoshi (for various smaller operations and for programming purposes).
Below, we present a full table of Bitcoin denomination units (We don't include grater units then 1 BTC as we do not see a reason while the Bitcoin price for today reached over $4700, I don't think anyone is using those MEGA units so they are meaningless.)