Bitnexa — Crypto Network Fees | bitnexa.net
How the mempool sets the sat/vB rate, how to estimate confirmation time and when a low fee is still safe.
Bitcoin fees are quoted in satoshis per virtual byte (sat/vB). Miners select transactions from the mempool, usually prioritising the highest sat/vB, so the rate you choose determines how quickly your transaction is included.
A transaction's virtual size depends on its inputs and outputs, not on the amount of BTC sent. A typical single-input, two-output transaction is around 140 vB, but consolidating many small inputs can make it much larger and raise the total fee at the same rate.
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Blocks arrive about every 10 minutes on average. A rate that would confirm in the next block at one moment may need more time if new transactions arrive with higher bids. Block explorers show a range of sat/vB bands with estimated confirmation windows.
1 satoshi equals 0.00000001 BTC. If you pay 20 sat/vB on a 140 vB transaction, the fee is 2,800 satoshis, or 0.000028 BTC. Confirm the total in BTC before broadcasting.
A transaction that is not mined simply waits in the mempool; it is not charged until it confirms. If the mempool clears, a low-rate transaction can confirm much sooner than expected.
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