Transactions per second (tps) is a metric used to calculate how many transactions a blockchain can process in a second. It is calculated using the below formula:
(Block Size/Transaction Size) / Block Time = Transactions Per Second
Note that a high amount of transactions per second does not necessarily result in a better blockchain. Referencing the blockchain trilemma, to some degree, projects may need to sacrifice decentralisation and security to achieve higher transactions per second through scalability.