check-sql-instance port.ps1

# You first need to get PID of SQL Server process - sqlservr.exe with this command:
tasklist|find /I "sql"
# It will give you output similar to this one:
# sqlwriter.exe                 2168 Services                   0      7,804 K
# sqlceip.exe                   2768 Services                   0     57,876 K
# sqlservr.exe                  4620 Services                   0    298,496 K
# sqlbrowser.exe                3488 Services                   0      4,752 K

# Take a note of PID for sqlservr.exe and use it to check ports which this process is listening
netstat -na | find "4620"
# You will get output similar to this one:
# TCP    0.0.0.0:50673          0.0.0.0:0              LISTENING       4620
# TCP    99.55.11.11:50673      10.32.1.90:52681       ESTABLISHED     4620
# TCP    127.0.0.1:50032        0.0.0.0:0              LISTENING       4620
# TCP    [::]:50673             [::]:0                 LISTENING       4620
# TCP    [::1]:50032            [::]:0                 LISTENING       4620

# In this case you instance port is 50673