After the segwit fork, instead of using block size, we use Block Weight. Bitcoin allows for 4,000,000 block weight, which is equivalent to 4MB when using only segwit.

1 MB legacy transactions are 4x as large as a segwit transaction. You save 75{c02dde72df927a7b1629fc29506cd3151b0442defda0d37a402db978ff19aaf8} on your transactions with segwit!