Bitcoin’s own source code limits the number of new Bitcoins that can ever be created to exactly 21 million units. Each new coin created slows down the creation process with the rate, on average, halving every four years.
This sets it apart from traditional currencies which can theoretically have infinite supply and grant Bitcoin an intrinsic value – similar to gold and other finite commodities. This means that over time, with all other conditions being equal, the value of Bitcoin is bound to witness a general upward trend as long as demand remains for it.