What is the Difference Between the Base Fee and the Priority Fee?
There are two types of fees that Solana charges, and they play different roles. There is the base fee, which is 5,000 lamports (0.000005 SOL – a sliver of a cent) per signature, and this pays for a signature to be included into a block. The priority fee is the extra payment that you can make to get better queuing in times of high competition for blockspace.
Here is a way to think about this. The base fee is the entry fee, much like buying a ticket to get into a theme park. That is a flat fee, and the base fee is also flat, whether you only do one signature or 100 signatures in one minute. The priority fee is like buying the express pass- unnecessary when the park is empty, but critical on Saturday afternoon when the line for the main attraction winds around the parking lot. You don't buy the pass just to get into the park. You buy it when all the other guests want to ride the same ride at the same time.
What Happens Technically Between the Two Fees
The base fee never changes. No matter the load on the network, no matter how much compute the transaction needs, the base fee is always 5,000 lamports per signature. At SOL prices around $80 that means a cost of $0.0004 per signature. 50% of that base fee gets burned, and 50% of that base fee gets paid to the leader, the validator that is currently building the block.
The priority fee works differently. You set it through the Compute Budget program of Solana, and you specify the cost of the priority fee in micro-lamports per compute unit (or "CU," the unit that Solana uses to measure the work performed by a transaction). If you pay 10,000 micro-lamports per CU for a transaction that uses 200,000 CUs, that adds a priority fee of 2,000 lamports (still less than a cent!). In times of contention, the leaders sort transactions by priority fee per CU, so your transaction will get higher placement in the queue with a higher priority fee per CU.
Also, a recent protocol change impacts the economics of validators, namely SIMD-0096, which became active in 2025 and pays 100% of the priority fee to the validators, where before 50% of the priority fee was burned. This gives leaders an explicit, protocol-level incentive to prioritize high bidders. They no longer need to seek a side-deal in order to squeeze in a transaction.
Comparison: How Solana's Fee Model Differs to Ethereum's Fee Model
Ethereum's EIP-1559 fee model features a base fee that rises in proportion with overall demand for the network. If any application is popular enough to drive up demand on the chain, the base fee becomes higher for all users, since everyone bids in one big block-space auction. In Solana, each half of this formula is inverted. The base fee always stays flat. When demand increases, the congestion price is raised only for those accounts competing for limited block-space, leaving the base fee and the non-competing accounts in other accounts.
To imagine this, picture a Saturday afternoon on a blockchain where a meme coin is released by pump.fun with 1,000 bots flooding a single memecoin pool. You open the Phantom Wallet and swap USDC into SOL on Jupiter, and you pay less than a cent for the swap fee, even during that surge, since you do not use any accounts in contention. In contrast, Ethereum saw gas prices for simple token swaps rise into the tens of dollars during the 2021-2022 bull run. All those users who just happened to be in the same queue as the other users during a surge were forced to pay more.
Why Does the Split Between the Fees Matter?
This model allows for a guaranteed minimum cost (the base fee) and an estimated, optional cost to get into a higher-transaction slot (the priority fee). You always know your minimum transaction cost, which is 5,000 lamports per signature. If you are bidding for a faster slot, you have the ability to estimate how much the slot costs. You pay a few thousand lamports to get priority over other transactions during normal conditions. You pay more during a Drift liquidation or a popular minting event that might be worth 3,000 lamports. Wallets like Phantom and services like the Helius RPC will estimate that value in real-time, and automatically attach a reasonable priority fee in order to land your transaction on-chain.
But it is important to note a couple of points here. You will pay slightly higher fees because the priority fee estimator is an estimate, so you might pay a premium in order to get the priority slot, even if there wasn't a lot of competition. Or you might pay a lower priority fee than needed in order to get your transaction processed on-chain quickly. In addition, fees are paid for execution only. If your transaction is processed, and then it fails due to its own logic errors, then it's already paid to go onto the chain.
Do Priority Fees Guarantee that a Transaction is Included in a Block?
Priority fees do not guarantee that a transaction gets included. It simply gives you a higher priority in the queue that a leader sorts the transactions by. In times of extremely high congestion, even a high-priority transaction can get skipped by a block, and the transaction will need to be retried by the sender before its blockhash times out.
