Check if two ranges of dates overlap [Excel Formulas]

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Check if two ranges of dates overlap using excel formulasWhile preparing a project plan, I had a strange problem. I wanted to highlight all the project tasks that fall with-in a certain date range. At the lowest level, the problem is like this:

There are 2 ranges of dates (a,b) and (x,y) and I want to know if they overlap (ie at least one date common between a,b and x,y)

The formula for testing such a thing seemed tricky at first. So I drew the conditions on paper to get clarity on what we should test. Evidently, there are 4 ways in dates (a,b) can overlap with dates (x,y) as shown below:

Conditions to check if two sets of dates overlap

Now, we can test for the overlap condition using a formula like this:

If x is between a and b
or a is between x and y
then overlap
else do not overlap

As you know, there is no formula in excel like isbetween(). So we have to break it up to 2 conditions and an AND() Formula. Finally the formula becomes,

=if(or(and(x>=a,x<=b),and(a>=x,a<=y)),"Overlap","Do not overlap")

Now, it seemed like quite a big formula for testing if 2 ranges of dates overlap.

So, I continued my quest for even shorter formula.

After sometime, I realized that if we test for non-overlap instead of overlap, we can write a shorter formula.

Do not understand? Let me explain.

While there are 4 ways in which (a,b) can overlap with (x,y), there are only two ways in which (a,b) cannot overlap with (x,y). See this to understand:

Conditions to check if two sets of dates do NOT overlap

Now, testing above conditions is very straight forward in excel.

the formula becomes, =if(or(y<a,b<x),"Do not overlap","Overlap")

The formula is much shorter and easy to maintain.

I was able to use it to test if a set of tasks in the project plan are running between given dates (for eg. next week). All is well in the end.

How do you test overlap conditions?

Do you ever have to test overlap conditions? What kind of formulas have you used? Please share your formula tips & tricks using comments.

Further Learning:

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21 Responses to “Distinct count in Excel pivot tables”

  1. Al says:

    The distinct count option works well but I have found that if I have a date field and want to group by year, month, etc. that option seems to be disabled. I need to do both, distinct count and group by year/month.
    Example data; sales orders with item quantities with dates.
    Challenge; sum the item quantities, count the distinct orders and group by month. How do I do this?
    Perhaps that's not possible due to the grouping?

    • Chandoo says:

      @Al... When you use data model based pivots, you cannot group values manually anymore. Why not use Excel 2016's default date grouping option? In this case we have just a few dates, so Excel is not grouping them, but if you have an year's worth of data, when you make the pivot with date in the row label area, Excel automatically groups them. If you have fewer dates or want to use your own grouping, just create a table with all dates, add columns with month, week, year etc. Then connect this table (these types of tables are usually called as calendar tables) to your data on date field as a relationship. Now you can create reports by month, quarter etc easily.

      • Dan says:

        Is this the only way to do it in 2013? I find it rather cumbersome to have to create another data table listing dates with the another column for MONTH() and YEAR() to be able to summarise data for senior level...

        • Chandoo says:

          I know people find adding calendar tables cumbersome, but it is a best practice and let's you add more layers of analysis quite easily. For example, adding analysis by weekday vs. weekend or by financial quarter or YTD calculations (you would need either Power Pivot DAX or some very carefully setup pivot table value field settings)

  2. NC says:

    I had absolutely no idea this was possible. Very useful, nice work!

  3. Pete says:

    Doesn't work for 2010 version though (or at least not my works version)

    • NARAYAN says:

      Hi ,

      The post has the following in it :

      These instructions work only in Excel 2016, Office 365 and Excel 2013.

  4. Sarah says:

    when i have 2 different Pivot tables, one without the enabled “Add this data to data model” option, and the other one with it enabled.. is there anyway i can link slicers between them?
    if the answer is NO,, what to do ?

  5. Edgar says:

    Quick note, the “Add this data to data model” option is not available for the Mac version.

  6. Steve Curtis says:

    perhaps outside scope of this article but I have found when I attempt to create a pivot table from an external data source (connection to a sql view) the "Add this data to data model" becomes greyed out. Anybody experienced and found a solution so I can start getting distinct count in my pivot tables?

  7. Kelly Nanfito says:

    Is there a way to still add a calculated field when using distinct count?

  8. Luna says:

    I found I can't change the date source after tick the " add this data to the data model", can you help to adv how to change the date source in such case?

  9. Chris says:

    Is there a way to update the source once you have added to the data model? I receive a new spreadsheet weekly and would like to update the connection so my tables pull from the new source.

  10. Ankit Moral says:

    A big Thank you. It worked.

  11. Mohapi says:

    Hi, have survey data that I need to analyze but the challenge is that my key fields are showing horizontally. I tried to transpose the fields using Power Query, but unfortunately the new fields are returning same values on a pivot table despite using distinct values

  12. sorina says:

    How I can a do a pivot table with discount conts in some columns and then generate shor report filter pages. pls it drives crazy

  13. ira says:

    Hi. Why grand total pivot of distinct count is 13? shouldn't it be 67?

  14. Asia says:

    Great Answer! Saved me lots of time!
    Thank you!!!

  15. Suresh says:

    Worked awesome! Thanks!!

  16. Mayank says:

    Hi Chandoo,
    I am using pivot tables for distinct count and now I need to update them with new set of data. But when I update the source data, all the columns and formatting of Pivot table disappears and I need to build it from Scratch.

    Is there a possibility that I can update the source data with new rows added and also retain my pivot tables?

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