Because the max blocksize of BTC is heavily crippled, max transactions per block is around 3,500ish. That puts us at about 500k transactions max per day (1 block every 10 min). So divide 500k by how many seconds are in a day (86,400) and you get slightly under 6 TPS. Whoever came up with 7 TPS probably did more accurate math than me.
Because the max blocksize of BTC is heavily crippled, max transactions per block is around 3,500ish. That puts us at about 500k transactions max per day (1 block every 10 min). So divide 500k by how many seconds are in a day (86,400) and you get slightly under 6 TPS. Whoever came up with 7 TPS probably did more accurate math than me.
Different transactions use different amounts of space so it’s always going to be a rough estimate.