Bitcoins are created through a process known as mining. Mining is the term used by those who contribute to processing transactions. Miners process and secure the network using specialized hardware that “mine” for new bitcoins. As “payment” for their contribution, they are awarded new bitcoins. This is how new bitcoins are generated.
New coins are created at a fixed and decreasing rate that is predictable. The number of coins created each year is halved over time until 21 million bitcoins are in circulation. At this point, bitcoin miners will be rewarded by transaction fees.
When a miner has successfully created a new hash, the block is sealed off and added to the block chain. 25 bitcoins are awarded to the miner who discovered the new hash. The number of bitcoins rewarded per block is cut in half every four years. Blocks are solved an approximate rate of 6 per hour.