statistics – How to calculate the Cronbach 's alpha from a set of 5 questions at the likert scale?

I have a series of questions on the scale of Likert. Each question has 5 possible answers: strongly agree, agree, neutral, disagree and strongly disagree. I want to measure the internal consistency of this set of questions. How should I do this? I've searched online for Cronbach's alpha formula and all use real value options. How can I transform a likert scale into real values? Thanks in advance!