How much can the gas fee be reduced after Ethereum switches to PoS?

The dispute over gas fees has been going on for many years. Now that Ethereum is about to switch to a POS chain, the biggest expectation is that the gas fee can be reduced to a very low level. Why?

Because the processing efficiency of POS is much higher than that of POW, and the network resource cost is also low enough, only the validator needs to pledge ETH to earn block rewards. The "hardware" cost of the network itself has been reduced many times.

So how much can the gas fee be reduced after Ethereum switches to POS? Curiosity drives me to try to predict from various angles.

The gas fee calculation is gas price multiplied by gas usage. The unit price of gas price is completely different in POS and POW chains. Gas usage is related to keywords such as transaction size, contract size, block size, priority transaction tip, etc.

First, let’s break down the gas fee on the POW chain in detail.

Assuming the gas price above.

We unpack the data packed into a block.

In this block with a height of 14454322, a total of 62 transfers and 19 contract calls are packed. Under normal circumstances, the transfer price is low and the contract call price is high.

The total value of these transactions was approximately 0.161922 ETH.

Looking at the size of this block and the gas price,

This block finally packed 31965 bytes of data, and the gas price was around 27gwei.

Because the block has a basic size, the basic size plus the transaction size is the block size. We don't have time to check the byte size of all transaction data and add them up. I tried to find an empty block and found that the empty block size is about 540 bytes.

That is to say, we can calculate the size of all transactions up to the block above to be 31425 bytes.

According to the data from eth.gas.station, the average transaction cost is about $1.96. The ETH price at the height of 14454322 was about $3,100. Based on $3,100, the gas fee for transactions in the block was about $500.

In this way, the 62 transfers in the block will cost about $122, and the remaining 19 contract calls will cost $378.

Why does it cost 378 US dollars to call 19 contracts? Through transaction inquiries, these called contracts are all involved in opensea's NFT interaction and uniswap v2's token trading. The average gas fee consumption of these transactions is 20 US dollars per time. For 19 transactions, the number of 378 US dollars appeared.

Judging from the above data, the price of storing 3.1 megabytes of data on the Ethereum chain is as high as $500. If the unit price of gas continues to rise, the price will be even more outrageous.

From such expensive data, let’s calculate what the data would be like after Ethereum is merged?

First, we need to look at the gas price on Kiln, the test network after the Ethereum merger. Currently, the transaction volume on Kiln is relatively low. This chain, which uses the beaconchain mechanism, is mainly used to test the merged data and the operation after the merger. Because beaconchain has not yet carried out actual transaction packaging and operation, it is only used to synchronize some data. Therefore, it is only effective on Kiln.

First we opened a block with only 1 transaction.

This block is 119605, the block size is 627 bytes, there is 1 transaction, but this block has no transaction gas fee consumption.

Here we can see a key information, the gas price has dropped to 0.000000007gwei. And because this packaged transaction is a reward distributed to the validator address, it is not included in the transaction. Therefore, such a block can calculate the size of a block without other transactions. In order to ensure that it can cope with various situations, by querying the empty block, it is found that the size of an empty block is still 540 bytes.

Because there are fewer transactions now, we found a block that contains 10 transactions.

But I found that all the transactions in this block did not consume gas, that is, they were all "system transactions" on the chain. So I looked for some transfer and contract call transactions in the transaction browser.

In a 40ETH transfer, we found some data showing

Transaction Fee

0.000016800000126 Ether

Gas Price

0.800000006 Gwei

Gas Limit

21,000

Priority Fee / Tip

0.000016799999979 Ether

Transaction Burnt Fee

0.000000000000147 Ether

Gas Used by Transaction

21,000 | 100%

In this transaction, 21,000 gas was used, totaling 0.0000168 ETH, at a price of approximately $0.052.

We checked the block that this transaction was packaged in, and found that there were 6 transfer transactions in the block, which cost a total of 0.0001008 ETH, about 0.312 USD. These 6 transactions took up a total of 730 bytes, and each transaction took up about 120 bytes.

In order to find a comparison, we continued to look for some contract call records. Through the query, we found the fees for a contract upload, a contract call, and token minting.

The above is a transaction generated by a token contract. The transaction used 0.021 ETH. Because the contract occupies about 6000 bytes of space, it uses 1120000 gas, which is a huge cost in the POS network.

In this contract, 6 user accounts spent a total of 0.006 ETH after successfully calling the contract, and each call cost about 0.001 ETH. At the price of ETH3000 US dollars, it is about 3U. This price is also due to the high gas fee caused by the large size of the contract.

Let’s look at token minting. In a dai stablecoin minting contract, a dai minting is shown below, which only costs 0.000036 ETH.

The size of this transaction is around 200 bytes.

In summary, after switching to POS, users' daily transfer fees are extremely low, but when projects upload some larger contracts, the gas fee will be higher, and users calling such contracts will also cost higher gas.

But compared with the cost of the POW chain, the gas consumption of POS is several orders of magnitude lower.