# Computing gas fees to store a plaintext blob

I'm doing some math to figure out how much it would cost to store a multiple KB text blob in a single transaction, but the number I'm getting is too low to make sense.

Let's say I want to store 20KB of plain text on chain:

Quantity Label
640,000 gas/kb (source)
20 kb
12,800,000 total gas required
252 gwei cost per gas (source)
3,225,600,000 total gwei required
0.000000001 ETH in GWEI
3.2256 Total ETH

The result I'm getting is telling me it would only cost 3.23 ETH to store 20KB of plaintext in a transaction, but I'm having a hard time believing this.

Where am I going wrong in my math?

## Data availability + processing : Storage

As per EIP-2229 and assuming that you are setting a value to storage keys not previously assigned the cost per SSTORE would be : `20000` (SSTORE) + `2210` (SETTING NEW KEY) so an increase of 10.5% to your information for SSTORE gas cost.

• For 1Kb : 32 SSTORE operations are required so : `710,720` gas.

• For 20 kb : `14,214,400` gas

Assuming a gas cost of `252` Gwei, that's a total gas cost of : `3.58` ETH.

You were not taking EIP-2229 into consideration, but your computation is fine.

The result I'm getting is telling me it would only cost 3.23 ETH to store 20KB of plaintext in a transaction, but I'm having a hard time believing this.

Me too, but not for the same reason as you apparently. This is `12,920` USD pre EIP-2229, and `14,320` USD now. That's a huge amount of money for such little amount of data.

## Only data availability : Calldata

If all you are only interested in data availability and don't need to process that stored data on chain in any way, you can take inspiration from the way Rollups store data to L1: using calldata instead of storage.

The cost of calldata is currently of 16 gas per byte (EIP-2028) and might very well be reduced with EIP-4448.

Just taking the current calldata cost for 20Kb that's : `16 * 1024 * 20` = `327,680` gas, assuming the same `252` Gwei gas price that's "only" `0.082` ETH or around `328` USD. (I'm taking the current ETH price : 4000 USD)

Which is obviously much better.