You could use Data|Validation
Allow Decimal between 0 and 1

(Times are just fractions of days.)

12:00 Noon is 12/24 = .5
8:00 PM is 20/24 = .8333

Be aware that data|validation isn't robust. You can copy|paste from a different
cell and break it.

ReneeM wrote:

I want to limit entry into certain cells to shift/ctrl/; (timestamp) so that
it can be used to keep track of actual time. How do I do this?

--

Dave Peterson