The TIMEVALUE function converts a given time string into the serial number representation of time in Google Sheets. For example, the formula =TIMEVALUE(“12:00 PM”) returns “0.50”, the numeric representation of time in Google Sheets.
time_string – Required. The given value of time to be converted into the serial number representation of Google Sheets’ proper time format.
If both date and time is given against the time_text argument, the function will ignore the date part of the given time.
If two time values are provided with a colon i.e. “02:20”, time will be treated as hour and minutes. For seconds, use this format “02:20:10”, which means 2 hours, 20 minutes and 10 seconds.
The #VALUE! error occurs if supplied value against the time_text argument is not a valid time value.
For more detail, visit Google official website.