How Ethereum Gas Fees Work: Base Fee and Priority Fee

Why Your Mint Fee Isn’t One Flat Number

If you have ever opened a wallet to mint an NFT and seen it ask you to confirm a “max fee” alongside an estimated total, you have run into one of the more confusing parts of using Ethereum and other EVM compatible chains. Since the London upgrade in 2021 (EIP 1559), the network fee you pay for any transaction, including an NFT mint, is actually made up of three separate pieces: the base fee, the priority fee, and the max fee you set as a ceiling. Understanding what each one does can help you avoid overpaying, and explains why the same mint can cost very different amounts depending on when you click confirm.

The Base Fee: Set by the Network, Not by You

The base fee is the minimum amount every transaction in a block must pay per unit of gas. You do not choose it, and neither does the person who built the NFT contract. It is calculated automatically by the protocol based on how full the previous block was.

• If a block is more than half full, the base fee rises slightly for the next block.
• If a block is less than half full, the base fee drops slightly.
• The base fee portion of what you pay is burned, meaning it is removed from circulation rather than paid to anyone.

This is why gas tracker sites show the price moving minute to minute even when nobody you know is doing anything. It is simply responding to overall network demand, including unrelated activity like token swaps or other mints happening at the same time as yours.

The Priority Fee: Your Tip to the Validator

On top of the base fee, you add a priority fee, often just called a tip. This part goes directly to the validator that includes your transaction in a block. A higher tip gives a validator more incentive to pick your transaction over others waiting in the queue.

During a popular NFT drop, many wallets are competing for a limited number of transaction slots in each block. Raising your priority fee slightly can help your mint go through sooner, though it does not guarantee anything if a contract is also using its own queuing logic, such as a limited allowlist window.

The Max Fee: Your Safety Ceiling

The max fee is the highest total amount per unit of gas you are willing to pay, combining an estimate of the base fee plus your chosen priority fee. Most wallets calculate a reasonable max fee for you automatically, but you can usually adjust it in advanced settings.

Here is the part that surprises a lot of first time minters: you are only ever charged the base fee at the time your transaction is confirmed, plus your priority fee. If you set a generous max fee as a buffer and the actual base fee turns out lower, you get the difference back. The max fee is a cap, not a guaranteed charge.

What Happens If You Set It Too Low

If your max fee is lower than the current base fee, your transaction simply will not be included in a block. It sits pending until the base fee drops below your cap, or you cancel and resubmit with a higher value. This is a common reason a mint seems “stuck” rather than failed outright.

What Happens If You Set It Too High

Setting an unnecessarily high max fee will not make your transaction go through faster by itself, since confirmation speed is driven mainly by the priority fee you offer, not the ceiling. The main risk of a high max fee is psychological: it can make a mint look far more expensive in your wallet’s confirmation screen than what you will actually pay once the transaction settles.

Does This Apply to Every Chain?

EIP 1559 style fee markets are used by Ethereum mainnet and most EVM compatible chains and Layer 2 networks, including Polygon and most Ethereum rollups, though exact parameters differ. Some chains, including certain Layer 2s, add a separate and usually much smaller data fee on top of execution gas. Non EVM chains such as Solana use entirely different fee models, so the base fee and priority fee split described here does not transfer directly to those networks. If you are unsure how a specific chain prices transactions, check that network’s own documentation before assuming Ethereum’s model applies.

Practical Tips for Minting Without Overpaying

• Check a live gas tracker before a scheduled drop. If the network is unusually busy, consider whether minting a few minutes later could cost less, when that fits the project’s mint window.
• Avoid panic raising your priority fee during a rush. A modest tip is often enough; large tips mostly help when you are racing other bots for a hard cap on supply.
• Remember that unused max fee is refunded. A cautious buffer protects your transaction from failing, it does not mean you will pay that full amount.
• If a mint keeps failing or staying pending, check whether your max fee is below the current base fee before assuming something is wrong with the contract.

Gas pricing can feel like one more technical hurdle between you and minting your first NFT, but the mechanics are consistent once you see the three pieces separately. If you are getting started with creating or minting digital collectibles, the Simple NFT Creator app walks you through the process on both iOS and Android, with clear fee estimates before you confirm. You can find it on the App Store and Google Play.