Display Relative Week Numbers in MS Project

Posted by Steve Wilheir under Gantt Charts, MS Project Tips

Sometimes you don’t want to throw hard dates around when communicating project timelines.  For example, when the customer writes a check, the project will take a certain amount of time, but the customer could delay for months as they do comparative analysis of buy vs. build, etc.   Here’s a handy tip when you want to draw a Gantt chart , if you’d like to show the relative week number from the project start next to milestone tasks in the WBS of the Gantt chart.  You need to insert a calculated text field in order to show week numbers in MS project.

Right click on the column header

  1. Select “Insert Column.”
  2. Select an unused custom text field name like “Text1”.
  3. Change the title to something like “Week #”. Now, you should see a blank column with the header “Week #” on it.
  4. Right click that new column header and choose “Customize Fields…”
  5. Click the “Formula…” button
  6. Type the following formula into the formula dialog:
    • CStr(1+DateDiff(“w”;[Project Start];[Start]))

Then you will see the relative number of weeks instead of dates in Microsoft project in your new column.  Just hide the date column if you don’t want to show it.

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8 Responses to “Display Relative Week Numbers in MS Project”
  1. Ron Holohan Says:


    As a project management blogger, would you be interested in being a guest blogger for The pm411.org Project Management Podcast website (www.pm411.org)? My subscribers would undoubtedly be interested in your viewpoint on any PM topic you choose and we would provide a link back to your site in the article to help drive additional traffic to your site.

  2. Supun Perera Says:

    Hey, thanks…..

    though this may have been a simple thing for you, it saved me a lot of time! Thanx!!


  3. PS Says:

    I’m getting a syntax error. It doesn’t like the “w” bit. any ideas?

  4. Nigel Charman Says:

    Thanks for the tip. Seems that in Project 2000 I had to re-type the “w” and change the semicolons for commas, but I got the column working. Now what I want is to actually show a Gantt chart with relative dates, not aboslute. This is for estimates where I want to say – it will take this long with staging from the start date – whatever that start date turns out to be…..
    Would be great if MS project could do that, but I suspect that it is another example of where MS project doesn’t work in the real world…

  5. Karen Says:

    Great tip! I am often trying to calculate this by hand and that is really handy to have a way to put that in automatically!

  6. Michelle Says:

    Thanks for the tip! I’ve also created a second column and changed the [start] to [finish] so I can see which project weeks my tasks run over.

    By changing my project start date, I have my start up tasks showing as -weeks and then the correct numbering for the project weeks.

    Just what I was after!!

  7. joseph Says:

    What W stand for in the formula? MS Project return me an error toward it…

  8. Alberto Says:

    Hi there:
    MS Project help is lame. I am using MSP 2010, formula that actually worked was
    CStr(1+DateDiff(“w”,[Project Start],[Start]))

    Notice that it uses comma (“,”) instead of semicolon (“;”). I also added

    & “w”

    to the end for display of units (weeks, in this case)

    Odd enough, when you paste it the first time, it’ll point at error on “w” token. Then you just erase the token and TYPE it back, and voila!!

    Note: “w” means it delivers the results in weeks, use “d” for days.

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