About block 917,280
Bitcoin block 917,280 was mined by F2Pool on October 1, 2025 at 7:57 PM UTC, 5 min 19 s after block 917,279. That is faster than the 10-minute average the network aims for: blocks come in bursts because finding one is pure chance.
It confirmed 1,556 transactions in 0.82 MB (48.1% of the 4 million weight-unit limit). The median transaction paid 1.00 sat/vB, and all fees added up to 0.0128 BTC. With the 3.125 BTC subsidy of halving era 5, F2Pool earned 3.1378 BTC for this block.
Block 917,280 is number 1 of 2,016 in difficulty epoch 455; 2,015 blocks remain until the next difficulty adjustment at block 919,295. The next halving is at block 1,050,000, 132,720 blocks after this one.
Its hash starts with 20 zeros: that is the proof of work, a number below the target that the whole network’s hashrate had to search for. F2Pool found 173 blocks in the week before. Today the block has 56,300 confirmations, so it is settled beyond any practical doubt.
Why block 917,280 is notable
Block 917,280 opens difficulty epoch 455. Every 2,016 blocks, each node recalculates the mining difficulty from how long the previous epoch took: if those blocks arrived in less than two weeks, difficulty goes up; if they took longer, it goes down, never by more than a factor of four. The new value, 150,839,487,445,891, took effect with this block, found by F2Pool on October 1, 2025 at 7:57 PM UTC, and applies until block 919,295; the following adjustment is at block 919,296.
Nobody schedules a retarget. It happens when the chain reaches the height, so the adjustment at block 917,280 came the moment F2Pool found it, not on a fixed date. The rule keeps the average close to one block every ten minutes however much hashrate joins or leaves the network.
Of the 3.13776335 BTC that F2Pool collected for this block, 3.125 BTC was new subsidy and 0.01276335 BTC came from fees, 0.4% of the total; leaving out the coinbase, its 1,555 transactions paid about 821 sats each on average.
Current difficulty epoch and next adjustment →
What’s inside a Bitcoin block
Every block, 917,280 included, is made of the same parts:
- Header
- Eighty bytes that miners hash over and over: the version, the hash of the previous block, the Merkle root that summarises every transaction, a timestamp, the difficulty target in compact form and a nonce. A block is valid when the hash of its header falls below the target.
- Coinbase transaction
- The first transaction, written by the miner. It spends no inputs: it creates the subsidy and collects the fees, and since BIP 34 it must also record the block height.
- Transactions
- Everything else in the block: payments taken from the mempool, usually picked by fee rate because space is capped at 4 million weight units. Block 917,280 holds 1,556, counting the coinbase.
- Fees
- The difference between what each transaction spends and what it creates. The miner claims them in the coinbase; they are the part of the reward set by demand rather than by the protocol.
- Subsidy
- New bitcoin created by the block, fixed by the halving schedule: 50 BTC at the start, halved every 210,000 blocks. At height 917,280 it is 3.125 BTC.