I Install SQL server in my system and I have to check on which port number SQL is working in my system
Open Run in your system.
Type %windir%\System32\cliconfg.exe
%windir%\System32\cliconfg.exe
Click on ok button then check that the "TCP/IP Network Protocol Default Value Setup" pop-up is open.
Highlight TCP/IP under the Enabled protocols window.
Click the Properties button.
Enter the new port number, then click OK.