I was bored at work today, so I figured I do some math to get an idea about what global on-chain adoption might look like. I’d never really bothered to look at the numbers, and modeling it is certainly a complex problem because there are a number of variables at play. I started with a few assumptions, which I’ll list here:
Number of Users: 7 Billion
Number of transactions per user, per day: 1.666 (50 tx/month – loosely based on my own economic activity)
Average TX Size: 225 bytes (typical size of a 1 input 2 output transaction)
Average Blocks / Day: 144 (1 block / 10 min)
With the above, the math to figure out how large a block would need to be to support that much activity is fairly simple:
Blocksize = USERS * (TX_PER_DAY / BLOCKS_PER_DAY) * SIZE_PER_TRANSACTION ~=18.3 GB
So if the above assumptions are reasonably close to accurate, we’d need ~18.3 Gigabyte blocks every ten minutes to support the global economy. Put another way, that would be a smidge over 135,000 transactions per second. If every transaction paid a fee of 1sat/byte, that would mean a block would contain around 183 BCH in fees – which is 1500% more than the current block reward. That last bit is quite encouraging because it indicates that fees could drop to less than 0.001 sat/byte or lower and miners would still earn what they earn today.
This very simple analysis also ignores the block-space required by applications like Memo.cash which run on top of the blockchain, so the absolute blocksize required would likely be higher than this.