Bitcoin is unique, however, since the block reward schedule is public. All Bitcoin users and miners know the approximate date of each halving, meaning the Bitcoin price may not be affected when the halving happens. Bitcoin’s first block halving happened on November 28, The block reward dropped from 50 bitcoins per block to 25 per block. The most popular and trusted block explorer and crypto transaction search engine. The easiest and most trusted transaction search engine and block explorer. Products. Wallet Buy Buying crypto like Bitcoin and Ether is as easy as verifying your identity, adding a payment method and clicking "Buy". Sign up for our Wallet today. Create Wallet. The magic number is not something specific to bitcoin. Magic numbers are used in computer science for both files and protocols. They identify the type of the file/data structure. A program receiving such a file/data structure can check the magic number and immediately know the supposed type of .
Block numbers bitcoinHow many blocks are there in blockchain as of today? - Bitcoin Stack Exchange
This ensures that any program parsing block chain transactions linearly will encounter each output before it is used as an input. If a block only has a coinbase transaction and one other transaction, the TXIDs of those two transactions are placed in order, concatenated as 64 raw bytes, and then SHA SHA hashed together to form the merkle root. If a block has three or more transactions, intermediate merkle tree rows are formed.
If there are more than two hashes in the second row, the process is repeated to create a third row and, if necessary, repeated further to create additional rows. Once a row is obtained with only two hashes, those hashes are concatenated and hashed to produce the merkle root. The target threshold is a bit unsigned integer which a header hash must be equal to or below in order for that header to be a valid part of the block chain.
As a base number, nBits can be quickly parsed as bytes the same way you might parse a decimal number in base scientific notation:. Although the target threshold should be an unsigned integer, the original nBits implementation inherits properties from a signed data class, allowing the target threshold to be negative if the high bit of the significand is set.
This is useless—the header hash is treated as an unsigned number, so it can never be equal to or lower than a negative target threshold. Bitcoin Core deals with this in two ways:. When parsing nBits, Bitcoin Core converts a negative target threshold into a target of zero, which the header hash can equal in theory, at least.
When creating a value for nBits, Bitcoin Core checks to see if it will produce an nBits which will be interpreted as negative; if so, it divides the significand by and increases the exponent by 1 to produce the same number with a different encoding. Difficulty 1, the minimum allowed difficulty, is represented on mainnet and the current testnet by the nBits value 0x1d00ffff. Under current consensus rules, a block is not valid unless its serialized size is less than or equal to 1 MB.
All fields described below are counted towards the serialized size. The block header in the format described in the block header section. Every transaction in this block, one after another, in raw transaction format. Transactions must appear in the data stream in the same order their TXIDs appeared in the first row of the merkle tree. See the merkle tree section for details. The first transaction in a block must be a coinbase transaction which should collect and spend any transaction fees paid by transactions included in this block.
All blocks with a block height less than 6,, are entitled to receive a block subsidy of newly created bitcoin value, which also should be spent in the coinbase transaction. The block subsidy started at 50 bitcoins and is being halved every , blocks—approximately once every four years. Together, the transaction fees and block subsidy are called the block reward. A coinbase transaction is invalid if it tries to spend more value than is available from the block reward.
Contribute Edit Page. The hashes are in internal byte order; the other values are all in little-endian order. Viewed 15k times. Active Oldest Votes. Generic version Rather than directly answer your question with an answer that would become outdated within a few minutes as the next block was discovered, here's a general way you can look up the current number of blocks in the blockchain: Go to this list of blockchain explorers.
Choose one or choose several and visit its website. Almost all of them on their main page display the heights of recent blocks. For Bitcoin Core users The getblockchaininfo RPC includes both the height of the highest downloaded block and the height of the highest valid-looking downloaded header.
David A. Harding David A. Harding Just in general I'm not sure querying multiple block explorers really decreases your chance of them being wrong, simply comparing the "balance" field for a given address will more than likely give you completely unique results on most of them.
Bitcoin True. I clarified that section; doing that made me realize that there's a simpler method possible using just Bitcoin Core, so I added that to the answer. Harding Nov 1 '15 at Jimmy Song Jimmy Song 7, 11 11 silver badges 31 31 bronze badges. As of September 20, There are blocks. Future Future This answer now is just already outdated two hours later. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.
The Overflow Blog. Podcast What can you program in just one tweet? Ciao Winter Bash ! Featured on Meta.