Overview
How to use
- 1
Upload your Source File (File A) where you want the new data to be appended.
- 2
Upload your Lookup Table (File B) which contains the reference information.
- 3
Select the "Match Key" (common column like ID or Email) for both spreadsheets.
- 4
Select the "Column to Fetch" from your reference file.
- 5
Click "Run VLOOKUP Merge" to process your data instantly.
- 6
Review the real-time preview and export your merged file as a high-precision Excel document.
Key Features
- Universal Excel & CSV Merger: Works with all modern spreadsheet formats.
- Advanced O(N) Lookup Logic: Handles large datasets in seconds using Hash Maps.
- Technical Accuracy: Preserves data types and formatting during the merge process.
- Privacy-First Architecture: 100% client-side processing; no data ever leaves your browser.
- Zero-Scroll Utility: Designed for immediate interaction with the tool at the top of the page.
- Professional Grade Export: Get clean, production-ready .xlsx files with a single click.
Scientific Logic & Formulas
Frequently Asked Questions
How does this online VLOOKUP compare to Microsoft Excel?
This browser-based tool is a faster alternative to manual Excel formulas. It automates the matching logic without requiring you to write `=VLOOKUP(...)` or `=XLOOKUP(...)`. Plus, it handles CSV and Excel files interchangeably with better performance on large datasets.
Is it safe to process sensitive business data here?
Absolutely. We use a "Local-Only" processing model. Unlike other online converters, your files are NEVER uploaded to a server. All data lookup happens inside your computer's RAM using secure JavaScript, ensuring your private spreadsheets remain 100% private.
What happens if a matching key is not found in the reference file?
If the tool scans the source file and finds no matching ID or key in the lookup table, it will append "N/A" to that row. This helps you quickly identify missing gaps in your dataset synchronization.
Can I use this as a CSV data lookup tool for large files?
Yes! Our tool is optimized for professional use, supporting large CSV and Excel files. Because it runs locally, the only limit is your device's memory, avoiding many common timeout issues found in server-side lookup tools.