How do I set up a cell in Excel to reject an in time if it is not equal to or
greater than 30 minutes?

Use Data Validation on the date entry cell.

From the menus Data Validation
Settings: Allow Decimal; Data Greater than or Equal to; 30

- John Michl

Thank you so much John. This does allow me to limit the entry to a great
then-equal to value. However what I am trying to accomplish is settting a
time within a timesheet which limits the employee to a meal break of at least
30 minutes. This procedure you describe only allows time to be 30 minutes, it
doesn't allow anything over, i.e, if they clock out at 12 noon it won't allow
them to clock back in unless it is 12:30. I only want it to stop them if they
are trying to return to work before their 30 minutes are up.

"John Michl" wrote:

Use Data Validation on the date entry cell.

From the menus Data Validation
Settings: Allow Decimal; Data Greater than or Equal to; 30

- John Michl

Change the data validation to:

Settings: Allow Time
Data Greater than or Equal to
Start Time: A1 + 1/48

Where A1 is the cell that contains the log out time. 30 minutes is
also 1/48 of a day so adding that to the log out time would give the
earliest log in time. Note this will be very picky. 29 minutes and 59
seconds would not be allowed.

- John

Thank you John, that did it :-)

"John Michl" wrote:

Change the data validation to:

Settings: Allow Time
Data Greater than or Equal to
Start Time: A1 + 1/48

Where A1 is the cell that contains the log out time. 30 minutes is
also 1/48 of a day so adding that to the log out time would give the
earliest log in time. Note this will be very picky. 29 minutes and 59
seconds would not be allowed.

- John