How to Add Holidays to Microsoft Project: Step-by-Step Calendar Setup

I spent three years at Microsoft watching teams struggle with project timelines because they forgot to account for holidays. The fix is simpler than most realize.

Microsoft Project has a built-in calendar system that lets you mark non-working days with just a few clicks. No spreadsheets, no manual date adjustments—just a clean, automated way to keep schedules realistic.

You’ll avoid those awkward moments when a deadline falls on Christmas Day or Labor Weekend. The best part? It works across all modern versions, from Project 2016 through the latest 365 release.

Once set up, your timelines adjust automatically, saving you from last-minute panic. Here’s how to do it right the first time.

What Youll Need

Instructions

This method keeps your project timeline accurate and prevents scheduling conflicts.

Launch Microsoft Project and open your project file. Navigate to the Project tab in the ribbon. In the Properties group, click Change Working Time. This opens the calendar management interface where you’ll define exceptions.

The Change Working Time dialog displays the project calendar with working days highlighted in blue. Here’s the thing—this is where most users get stuck because they don’t realize you need to modify the calendar for the entire project, not just individual tasks.

In the Change Working Time dialog, select the calendar you want to modify from the For calendar dropdown (usually Standard). Click on the date of the holiday in the calendar grid. For multiple holidays, hold Ctrl while clicking each date.

Click the Exceptions tab, then type a name for the holiday in the Name field. Set the Start and Finish dates to the same day for single-day holidays. For multi-day holidays like Thanksgiving weekend, set the range accordingly. Click OK to save.

After adding exceptions, switch to the Gantt Chart view. Check that tasks scheduled on holiday dates now show as non-working time (typically grayed out). If a task spans a holiday, it should automatically adjust to exclude that day from its duration.

I always recommend scrolling through the entire timeline to catch any holidays that might have been missed. Don’t skip this (I learned the hard way) — a missed holiday can throw off your entire project schedule by days or even weeks.

If you’re using resource-level calendars, you’ll need to apply the same holidays there. Go to View > Resource Sheet, then double-click a resource name. In the Resource Information dialog, go to the Working Time tab and repeat the exception process.

Real talk: This step is often overlooked, which means resources might still be scheduled to work on holidays even if the project calendar shows them as non-working. Always verify both project and resource calendars for consistency.

Tips and Common Mistakes

These practical insights will help you avoid common pitfalls when setting up holidays in Microsoft Project.

The Calendar Scope: In Step 1, remember you’re modifying the entire project calendar, not individual tasks. I’ve seen too many users waste time trying to adjust task-level exceptions when the system requires calendar-wide changes. This is non-negotiable for proper holiday implementation.

Multi-Day Holiday Strategy: For Step 2, when dealing with holidays like Thanksgiving weekend, setting the Start and Finish dates to the same day only works for single-day holidays. For multi-day exceptions, you must set the full date range in the Exceptions tab to ensure all days are properly marked as non-working.

Verification Necessity: Step 3’s verification is critical—don’t just assume the system worked. I learned this after a major project timeline was thrown off by three missed holidays. Scroll through your entire timeline in Gantt Chart view to confirm all holidays appear as non-working time.

Resource Calendar Overlap: As mentioned in Step 4, this is the most commonly overlooked step. Even if your project calendar shows holidays correctly, resource-level calendars often don’t inherit these exceptions. Always double-check both to prevent scheduling conflicts where resources appear available on holidays.

Frequently Asked Questions

Adding holidays to Microsoft Project ensures accurate scheduling and realistic timelines. With just a few clicks, you can customize your project calendar to reflect non-working days. Now that you’ve mastered this, try applying these settings to a real project and see the difference it makes! 🎯