Here is a familiar problem:
You create a workbook to track some data. You ask your staff to fill up the data. Almost all the input data is fine, except the date column. Every one types dates in their own format.
Here is a fun, simple & powerful way to warn your users when they enter wrong dates.
Use conditional formatting
Here is a quick demo:
How to ensure cleaner dates with conditional formatting?
- Let’s say your users need to enter date input in cell C3.
- Select C3 and go to Home > Conditional Formatting > New Rule
- Select the rule type as “Use a formula…”
- Use a formula like this: =ISERROR(DAY($C$3))
- Set up formatting to highlight incorrect dates
- Done
Explanation for the formula:
We will assume that C3 contains a valid date and try to do some sort of date operation on it, like finding the day of month using DAY($C$3). If this returns an error, that means we have an invalid date.
So to check the error status, we use ISERROR().
A caveat: dates are numbers
Since Excel dates are numbers, technically, your users can type a number in C3 (like 7) and our conditional formatting won’t trigger the error.
Bonus tip: Adding conditional formatting to an entire column
To add conditional formatting to an entire column,
- Let’s say the date inputs go to column C, starting with C3 as first input
- Select all the cells in column C that will have dates
- Set up the conditional formatting with below rule:
- =ISERROR(DAY($C3))
Download example workbook
Click here to download a simple example workbook with this technique. Examine the conditional formatting in C3 & D3 to learn more.
Do you use CF to nudge your users in right direction?
Excel Conditional Formatting is one of my all time favourite features. I use liberal amounts of CF on all my Excel recipes. I think CF makes a great ingredient if you are collecting user inputs.
What about you? Do you use conditional formatting to make sure your inputs are clean? What techniques do you use? Please share your thoughts and tips in the comments area.
Here are few more awesome ways to use conditional formatting:
11 Responses to “FREE Calendar & Planner Excel Template for 2025”
Hi,
I downloaded this 2025 Calendar template. I checked the custom tab. Is it possible to change the weekend Fri & Sat.
Thanks
It is. Just use the option for fri & sat weekend (should be 7).
Activities of some dates are not getting displayed on "Any month" and "printable calendar" sheets.
e.g. Activity of 24 Apr 25.
Can you check again? The date in "planner" sheet should be a proper date. When I tested with 24-apr-2025, it works.
Love this calendar... I have highlight planner dates enabled but all dates are blue, is it possible to customize the color based on the type assigned to each date?
What would be the right way to add more Holidays in the Customizations?
Inserting rows in the Holiday List causes the blank cells in the calendar to turn Blue.
This is amazing!!! The best I've seen so far!! Is it possible to update it to consider a column for the final date? That way, if an event lasts more than one day, it repeats in the calendar
How do we change/insert the customization "Icon Options" ?
You can adjust these from the settings tab.
Is there anyway this can turn into an academic calendar (ie. start month is July and runs all the way through June of next year)?
Is there a way to make it something that is more than a day without having to add it to every day of that week.