Incorrect Gantt Tooltip Dates

What's Causing the Issue

1. Tooltip Date Format Conversion
   The Gantt visual often defaults to US-style MM/DD/YYYY formatting in tooltips, even if your model or system locale is set to DD/MM/YYYY. This is due to how the visual renders tooltips independently of Power BI’s global formatting settings.
2. End Date Showing +24 Hours
   This usually happens when:

• The Gantt visual interprets the end date as exclusive rather than inclusive.
• The time component is missing or defaulted to 00:00:00, causing the visual to assume the task ends at the start of the next day.

Workarounds and Fixes

1. Explicitly Format Dates as Text

Create new columns using DAX to format your dates exactly as you want:

FormattedStartDate = FORMAT([StartDate], "DD/MM/YYYY HH:mm") FormattedEndDate = FORMAT([EndDate], "DD/MM/YYYY HH:mm")

Then use these columns in the tooltip field instead of the raw date/time fields. This bypasses the visual’s internal formatting logic.

2. Adjust End Date by Subtracting a Minute

If the end date is being interpreted as the next day, try subtracting a small time increment:

AdjustedEndDate = [EndDate] - TIME(0,1,0)

This keeps the date within the expected range without affecting your actual data logic.

3. Check Locale Settings

Ensure your Power BI Desktop or Service is set to the correct regional locale (e.g., UK for DD/MM/YYYY). You can find this under:

• Power BI Desktop: File > Options > Regional Settings
• Power BI Service: Settings > Language and Region

4. Use a Custom Tooltip Page

If the built-in tooltip is too rigid, create a custom tooltip report page with full control over formatting. Then assign it to your Gantt visual under Visual > Tooltip > Report Page.

- Wrong End Date: Gantt tooltips often add +24h if the task ends at the same time next day (e.g., 9 AM to 9 AM).
- Date Format Flip: Tooltips default to MM/DD/YYYY, ignoring your locale.
- Fixes:
- Use FORMAT() in DAX to create custom tooltip fields.
- Convert datetime to text for tooltips.
- Check duration logic to avoid rounding errors.
- Set Power BI regional settings to your preferred locale.

Thankyou, anilgavhane and Shahid12523 for your responses.

Hi Wluka,

We appreciate your inquiry through the Microsoft Fabric Community Forum.

We would like to inquire whether have you got the chance to check the solutions provided by anilgavhane and Shahid12523 to resolve the issue. We hope the information provided helps to clear the query.
Should you have any further queries, kindly feel free to contact the Microsoft Fabric community.

Thank you.

Hi Wluka,

We are following up to see if what we shared solved your issue. If you need more support, please reach out to the Microsoft Fabric community.

Thank you.

Hi Wluka,

We wanted to see if the information we gave helped fix your problem. If you need more help, please feel free to contact the Microsoft Fabric community.

Thank you.