n8n Workflow: Outlook Timesheet CSV → Project Control Excel

Turns Outlook timesheet emails into an updated Project Control Excel workbook—automatically

This n8n workflow monitors Microsoft Outlook for unread emails with an Excel template and a timesheet CSV, then uses Microsoft OneDrive and Microsoft Graph Excel APIs to calculate person-days, deviations, and traffic-light status—finally replying to the email with the updated workbook.

What this workflow does

• Runs every 5 minutes to fetch the latest unread Microsoft Outlook email that contains attachments.
• Downloads and validates attachments: it identifies the Excel template and the timesheet CSV by filename keywords and fails if either file is missing.
• Uploads the Excel template to Microsoft OneDrive, then uses the Microsoft Graph Excel API to detect the used range and dynamically generate the required month/name/plan/actual ranges.
• Processes plan vs. actual data: it reads PLAN and existing IST values from the template, parses the CSV to aggregate hours per person per month, and converts hours to person-days (hours ÷ 8).
• Computes deviations and status for the reported month, including a monthly traffic-light indicator, and prepares cell updates (including a monthly IST sum formula).
• Writes updates back cell-by-cell via Microsoft Graph Excel APIs, including fixing missing/incorrect formulas.
• Updates “Kumulgrundlage” by adding or correcting the current month’s cumulative values in an Excel workbook session.
• Sends a reply in Outlook with a text summary and the re-downloaded updated workbook from OneDrive.

Use cases

• Project controlling teams who receive monthly timesheets via email and need IST and cumulative (“Kumulgrundlage”) updates fast.
• SaaS operators and automation engineers streamlining month-end reporting using n8n + Microsoft 365.
• Organizations standardizing plan-vs-actual tracking with consistent person-day calculations and automated deviation status.

Technical details

• n8n workflow nodes include: if, code, merge, sticky note, http request, and split in batches.
• Integrates with Microsoft Outlook (unread emails with attachments), Microsoft OneDrive (template upload/download), and Microsoft Graph Excel APIs (range detection and Excel cell updates).