Bitcoin operates on a fixed supply model, making it one of the most unique digital assets in the world. Unlike fiat currencies that can be printed endlessly, Bitcoin{:target="_blank" rel="dofollow"} has a hard cap of 21 million coins. But what happens when all bitcoins are mined? And how much Bitcoin is left to mine? Will Bitcoin remain viable, and how will the network sustain itself? Let's break it down.How many bitcoins are there?Do you know how many bitcoins are there? Or how many bitcoins are left? So far, more than 19.6 million of total number of Bitcoins have been mined, leaving only a tiny fraction to be mined. In every 10-minute timeframe, a new block of the network is found by miners and is incentivized in freshly minted BTC. Yet, the issue rate slows down with each new so-called Bitcoin halving happening approximately once every four years.How Many Bitcoins Are Left?There are, at the moment, less than 1.4 million BTC left to be mined. As big as this number might seem, considering how the mining rewards are designed, it becomes reasonable. At any rate, by design, because of the reduction in mining reward over time, the last Bitcoin will probably not be mined before the year 2140.What Will Happen When All Bitcoins Have Been Mined?Once the final Bitcoin is mined, miners will no longer receive block rewards. Instead, they will rely solely on transaction fees to sustain the network. While block rewards have been the primary incentive for miners, the expectation is that by 2140, Bitcoin transactions will generate enough fees to keep miners profitable.Key consequences of Bitcoin's fixed supply:Mining revenue change: miners receive fees for processing transactions instead of block rewards in the form of newly minted coins.Increased scarcity drives value: no more new BTC in circulation, and Bitcoin becomes more valuable because of that supply-demand dynamic.Totally decentralized economy: Bitcoin will only live by network activity and by those who use the network will also completely define the economic model of the network.Is Bitcoin Finite?Yes. Bitcoin has a capped supply of 21 million coins, and therefore no more can be ever created beyond that. Unlike gold or fiat money, which could be inflated over time, Bitcoin remains fixed and predictable as it has limited total supply of bitcoin. For this reason, many investors look at it as digital gold.How Will the Bitcoin Network Survive?The future of Bitcoin, post-mining, greatly depends on whether transaction fees will be sustainable. A few possibilities might help maintain the network:Higher Transaction Fees: Users of Bitcoin, with increased adoption, will pay higher fees for priority processing of the transaction.Layer-2 Solution: Certain technologies, such as the Lightning Network, allow for cheaper and faster transactions to help sustain the long-term utility of Bitcoin.Institutional Adoption: With more companies and governments recognizing Bitcoin as an asset class, demand for transactions will likely keep miners incentivized.Final ThoughtsWhile the last Bitcoin will not be mined for over a century, a supply cap is important to understand its long-term value proposition. Bitcoin's deflationary model makes it one of the rarest and most wanted digital assets. As we move toward a world where mining rewards for BTC disappear, it is transaction fees and network effects that will drive its future. Whether Bitcoin remains a dominant asset depends on adoption, security, and the willingness of users to sustain its economy. But one thing is certain---its hard cap of 21 million BTC ensures absolute scarcity, a quality that no other financial asset can replicate.