A função Timevalue( )

Google Sheets

Returns the fraction of a 24-hour day the time represents.

For example, if you enter "=TIMEVALUE("10:30 AM")" in a cell it will return the value "0.4375", which represents 10:30 AM as a fraction of a 24-hour day. This value can then be formatted as a time using time formats to display the time in a more human-readable way (e.g. "10:30 AM").

Retirado de: https://sheetshelp.com/timevalue

Here are some related formulas that you may find useful when working with time data in Google Sheets:

TIME: This function allows you to create a time value from separate hour, minute, and second values. For example, =TIME(15, 30, 0) will return a time value representing 15:30.
DATEVALUE: Similar to the TIMEVALUE function, the DATEVALUE function allows you to convert a date represented as a text string into a serial number, which can be used in calculations or formatted as a date value.
TEXT: The TEXT function allows you to format a numeric value as a text string, using a specified format. This can be useful for displaying the result of a TIMEVALUE formula as a time value.
HOUR, MINUTE, and SECOND: These functions allow you to extract the hour, minute, or second component from a time value, respectively. For example, =HOUR(TIMEVALUE("15:30")) will return the number 15.
DATEDIF: This function calculates the difference between two dates, in a specified unit (such as days, months, or years). This can be useful for comparing time values or calculating durations.