Regular expression for matching HH:MM time format

I want a regexp for matching time in HH:MM format. Here's what I have, and it works:

^[0-2][0-3]:[0-5][0-9]$

This matches everything from 00:00 to 23:59.

However, I want to change it so 0:00 and 1:00, etc are also matched as well as 00:00 and 01:30. I.e to make the leftmost digit optional, to match HH:MM as well as H:MM.

Any ideas how to make that change? I need this to work in javascript as well as php.

Solution 1:

Your original regular expression has flaws: it wouldn't match 04:00 for example.

This may work better:

^([0-1]?[0-9]|2[0-3]):[0-5][0-9]$

Solution 2:

Regular Expressions for Time

• HH:MM 12-hour format, optional leading 0

    /^(0?[1-9]|1[0-2]):[0-5][0-9]$/
  

• HH:MM 12-hour format, optional leading 0, mandatory meridiems (AM/PM)

    /((1[0-2]|0?[1-9]):([0-5][0-9]) ?([AaPp][Mm]))/
  

• HH:MM 24-hour with leading 0

   /^(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]$/
  

• HH:MM 24-hour format, optional leading 0

   /^([0-9]|0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]$/
  

• HH:MM:SS 24-hour format with leading 0

   /(?:[01]\d|2[0-3]):(?:[0-5]\d):(?:[0-5]\d)/
  

Reference and Demo