How is the value of bitcoin calculated

Since it is not regulated by central authorities nor governments, the value of bitcoin is calculated based on demand and supply in a particular moment. This is the reason why different exchanges have different prices, because it depends on the demand and supply on their platform. At the moment, the daily fluctuation of bitcoin price is relatively high. The causes count the novelty of the technology, its low market capitalization and the high speculation to which bitcoin is subject to.