iIf you come out of the Staephenson Street exits about 15 minutes, if you come out of either Station Street or Smallbrook Queensway exit could be up to 25 minutes.
you will also need to take care over route because need to cross Great Charles St Queensway, and only limited options - either Newhall Street or Ludgate Hill footbridge but you need to know where the steps are on the city centre side. Other option is at St Chads by the far end of Snow Hill Station but this involves a slight double back