# EIP-1559 fee structure terminology

Looking at the fee structure of the EIP - 1559, I noticed we have such terms as `maxPriorityFeePerGas` and `maxFeePerGas.` I think `maxPriorityFeePerGas` is basically tip you pay the miner and `maxFeePerGas` is the maximum amount you are wiling to pay.

My question is, where does `PerGas` come from? Aren't they really `maxPriorityFeePerGas` and `maxFeePerGas`?

Gas is the measure of computation required to execute your transaction, depending on what functions your contract uses the gas used changes. This is analogous to the transaction bytes size in Bitcoin transactions.

The fees you set are how much gwei you are willing to pay for each gas unit, that's why it's `PerGas`. It's analogous to the `satoshi/vbytes` in Bitcoin transactions.

So for example, let's say my contract has a function that spends 130k gas and I set the `maxFeePerGas` to `50`, then I'll be paying maximum `130000 * 50 = 6500000 gwei = 0.0065 ether`.

And you're correct about `maxPriorityFeePerGas` and `maxFeePerGas`, but just to make it crystal clear:

`maxPriorityFeePerGas` is a tip you'll be paying to the miner so that your transaction is processed before others.

`maxFeePerGas` is the maximum you'll be paying in total as `baseFeePerGas + PriorityFeePerGas`, where `baseFeePerGas` is calculated by the protocol.

You always pay the `baseFeePerGas`, if that's below `maxFeePerGas` the rest will be paid to the miner if `maxPriorityFeePerGas` is above zero. The paid priority fee can be lower depending on the maximum fee set.

E.g.

``````70 = maxFeePerGas
30 = maxPriorityFeePerGas
50 = baseFeePerGas
``````

You'll pay only 20 as priority fee because that's what's left between maximum and base fees.