> For the complete documentation index, see [llms.txt](https://faq.blink.sv/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://faq.blink.sv/transaction-fees/what-determines-mining-fees.md).

# What determines mining fees?

The amount of fees you need to pay for a Bitcoin on-chain transaction is determined by two factors:

1. Network congestion: When there are many pending transactions waiting to be confirmed, the fees tend to go up to incentivize miners to prioritize your transaction.
2. Transaction size: The larger your transaction in bytes, the more fees you will need to pay as miners prioritize transactions with larger fees per byte.

Therefore, during times of high network congestion, fees can increase significantly, making transactions more expensive. It's always recommended to check the current network conditions before sending a transaction to ensure you're paying an appropriate fee.


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