Time formulas

[Scarless87]

Hi there! Need an excel time formula.

I need to make all the cells in column C turn red if a time entered in the connected column B cell has passed four hours.

Then I need the cell in column C to turn back to white once a time has been entered.

For example:
If I enter 12 pm in B2 and four hours goes by, I need C2 to turn red. Once I enter a time in C2, I need the cell to turn back to white.

Any help would be appreciated. I only know how to do this with days.

[HansV]

Welcome to Eileen's Lounge!

Select the range in column C that you want to format, from C2 down. C2 should be the active cell in the selection.
On the Home tab of the ribbon, click Conditional Formatting > New Rule...
Select 'Use a formula to determine which cells to format'.
Enter the formula

=AND(B2<>"", B2<MOD(NOW()-TIME(4, 0, 0), 1), C2="")

Click Format...
Activate the Fill tab.
Select red as highlight color.
Click OK, then click OK again.

[Scarless87]

That worked! Thank you!