Transaction Fee

A transaction fee is what you pay miners to include your Bitcoin transaction in a block. Mechanically, it's the difference between the sum of input values and the sum of output values - whatever you don't explicitly send to an output, the miner who confirms the transaction collects.

Fees are quoted as a rate, not a total: sats per virtual byte (sat/vB). A larger transaction costs more in fees at the same rate. Typical transaction sizes:

• Simple P2WPKH (1 input, 2 outputs): ~140 vB
• Taproot (1 input, 2 outputs): ~110 vB
• 2-of-3 multisig: ~250 vB
• Consolidations with many inputs: 500+ vB

At 10 sat/vB, those would cost 1,400 / 1,100 / 2,500 / 5,000+ sats respectively. Real fees vary wildly depending on network congestion.

The fee market dynamics:

• Low-congestion periods. Fees drop to 1-3 sat/vB, and in 2026 often below 1 sat/vB. Most transactions confirm in the next block at those rates.
• High-congestion periods. Fees spike. When the Runes token protocol launched at the halving block on April 20, 2024, the median fee rate in mined blocks averaged more than 1,000 sat/vB for several hours.
• Estimator-driven defaults. Your wallet uses fee estimation to pick a reasonable rate. Most wallets get this right; you can override if you understand the trade-off.
• Fee bumping (RBF, CPFP) is available if you underpaid and got stuck.

Long-term, transaction fees are meant to become the incentive for miners. In the year to October 2026 they were about 0.6% of block reward revenue (about 6.5% in 2024). As the block subsidy halves toward zero around 2140, fees become 100% of it. Whether the fee market will be big enough by then to pay for strong security is an open question.

See live mempool fee bands on the Node page or in the Mining rabbit hole section 6.