The fastest option to get from St Pancras to Paddington is the Circle Line or Hammersmith & City Line from King's Cross St Pancras station. It’s just five stops and takes around eight minutes, with no changes required.
You could take a cab from St Pancras to Paddington, travelling down Euston Road with a journey time of around 10 minutes. Alternatively, if you have time to walk and fancy a stroll in the fresh air, it should take you around 35-40 minutes. You can also take the bus and jump on the 46 to Paddington.
It’s important to know that St Pancras and King’s Cross stations are right next door to each other, and you can walk between them in minutes. They share a tube station too: King’s Cross St Pancras.