Use the DATEDIF function

Calculates the number of days, months, or years between two dates.

=DATEDIF(start_date, end_date, Unit)

start_date: the first date of a given period, end_date: the last date of a given period,
Unit is "Y" for full years, "M" for full months, and "D" for full days. Explicit dates and units must be quoted in the formula. 

For example: =DATEDIF("10/24/23",E9,"D"), where D9 is start date, E9 is end date, and "D" is the number of full day between the two dates.

For more options, see DATEDIF function.

Calculates the number of days, months, or years between two dates.

=DATEDIF(start_date, end_date, Unit)

start_date: the first date of a given period, end_date: the last date of a given period,
Unit is "Y" for full years, "M" for full months, and "D" for full days. Explicit dates and units must be quoted in the formula. 

For example: =DATEDIF("10/24/23",E9,"D"), where D9 is start date, E9 is end date, and "D" is the number of full day between the two dates.

For more options, see DATEDIF function.

Calculates the number of days, months, or years between two dates.

=DATEDIF(start_date, end_date, Unit)

start_date: the first date of a given period, end_date: the last date of a given period,
Unit is "Y" for full years, "M" for full months, and "D" for full days. Explicit dates and units must be quoted in the formula. 

For example: =DATEDIF("10/24/23",E9,"D"), where D9 is start date, E9 is end date, and "D" is the number of full day between the two dates.

For more options, see DATEDIF function.