I know this a a joke but in case some people are actually curious:
The manufacturer gives the capacity in Terabytes (= 1 Trillion Bytes) and the operating system probably shows it in Tebibytes (1024^4 Bytes ≈ 1.1 Trillion Bytes).
So 2 Terabytes are two trillion bytes which is approximately 1.82 Tebibytes
I know this a a joke but in case some people are actually curious: The manufacturer gives the capacity in Terabytes (= 1 Trillion Bytes) and the operating system probably shows it in Tebibytes (1024^4 Bytes ≈ 1.1 Trillion Bytes). So 2 Terabytes are two trillion bytes which is approximately 1.82 Tebibytes