What is a Priority Fee?
The priority fee (also called the “tip”) is the user-set amount paid to validators to incentivize faster transaction inclusion. It’s the portion of gas fees that goes to the validator, on top of the protocol-set base fee (which is burned).
How Priority Fees Work
Your total gas price has two components:
Total Gas Price = Base Fee (burned) + Priority Fee (to validator)
- Base fee: Protocol-determined, automatically adjusts — you have no control
- Priority fee: You set it — higher tip = faster inclusion
Setting the Right Priority Fee
| Situation | Priority Fee | Result |
|---|---|---|
| Not urgent | 1 gwei or less | Confirmed when network is quiet |
| Normal | 1-2 gwei | Confirmed within a few blocks |
| Urgent (DEX swap) | 2-5 gwei | Confirmed in the next 1-2 blocks |
| Critical (liquidation) | 10+ gwei | Confirmed immediately |
During periods of low network activity, even a 0 gwei priority fee is sufficient — the base fee alone gets you included. During gas wars, you need high priority fees to outbid other users.
Priority Fees and MEV
MEV bots use very high priority fees to ensure their transactions are included at exactly the right position in the block:
- A sandwich attacker might pay 90%+ of their profit as a priority fee
- The validator captures this priority fee, making MEV extraction profitable for validators
- This is why validators earn more from MEV-boost than from standard block rewards
Frequently Asked Questions
Q: What happens if I set my priority fee to 0? A: Your transaction will still be included — eventually. It will be processed after all transactions with priority fees. During busy periods, a 0-priority-fee transaction might wait for many blocks or get dropped.
Q: Do I get back unused priority fee? A: Yes. The priority fee is only charged on the gas actually used. If you set a max priority fee of 5 gwei but your transaction is simple, you only pay the priority fee for gas consumed. Unused gas is refunded.
Q: How do I know what priority fee to set? A: Most wallets (MetaMask, Rabby) auto-estimate the appropriate priority fee based on current network conditions. For advanced users, monitoring block space utilization on block explorers (e.g., Etherscan Gas Tracker) helps you set fees manually.