---
# System prepended metadata

title: <center><i class="fa fa-edit"></i> 4.6 Transaction Fees </center>
tags: [Blockchain]

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# <center><i class="fa fa-edit"></i> 4.6 Transaction Fees </center>
###### tags: `Blockchain`
The following notes are taken from [Coursera](https://www.coursera.org/learn/cryptocurrency/home/week/2)

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Definition:
```
transaction fee = value of inputs - value of outputs
```
- Fee goes to miner who records the transaction 
- Cost resources for 
    - Peers to relay your transaction 
    - Miner to record your transaction 
- Transaction fee compensates for (some of) these costs
- Generally, higher fee means transaction will be forwarded and recorded faster

### Current Consensus Fees
- No fee if:
    - tx less than 1000 bytes in size
    - All outputs are 0.01 BTC or larger, and
    - Priority is large enough
        - `Priority = (sum of inputAge*inputValue) / (trans size)`
- Otherwise fee is 0.0001 BTC per 1000 bytes
- Approx transaction size: `148 Nᵢₙₚᵤₜₛ + 34 Nₒᵤₜₚᵤₜₛ + 10`
    - 10 for other information 

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- Most miners enforce the consensus fee structure
- If you don't pay the consensus fee, your transaction will take longer to be recorded
- Miners prioritize transaction based on fees and the priority formula 