> For the complete documentation index, see [llms.txt](https://docs.vanarchain.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.vanarchain.com/getting-started/vanar-architecture/fixed-fees/how-it-works.md).

# How it works

The protocol keeps record of the transaction fees for the tier 1 transactions in block headers with the key 'feePerTx'. 

In the screenshot below showing details of a block (block number 3,794,620 on testnet) you can see the transaction fees as well that is applicable to the tier 1 transactions (transaction requiring max of 12,000,000 gas). If a transaction falls in any other subsequent tier, then the protocol uses the same transaction fees value and a multiplying factor applicable to the subject tier to know the gas price for the subject transaction. For example for a tier 2 transaction it will be multiplied by 1500 (that is 0.0005 \* 1500 = 0.75$ in terms of USD value)

<figure><img src="/files/eURreHEqp4m71UVdIHs3" alt=""><figcaption></figcaption></figure>

In the screenshot below you can see the exact same fees being charged to a transaction that falls under tier 1. This is is one of the transactions in the same block for which details are shown above.

<figure><img src="/files/Jbr8B8DPocXaXlb3to7j" alt=""><figcaption></figcaption></figure>