100% local and secure
Your data stays on your device and is never sent to our servers.
CSV Merge
Combine rows from several CSV files into one result, align compatible columns consistently, and download the merged file directly.
- 100% local
- Instant
- Free
- No account
- Works offline
- Clipboard
Data not sent
Data not sent
Merged CSV
Why use this tool?
Merge two CSV datasets by validating matching headers or automatically combining their columns.
Smart processing
Clean, structure, and transform your data with rules tailored to the format being processed.
Supported formats
CSV, XLSX, and other tabular formats depending on each tool’s capabilities.
Save time
Get a clean, ready-to-use result in seconds without installing software or configuring a complex workflow.
Fonctionnement
How does this tool work?
The tool reads every selected CSV file, aligns the columns according to the chosen merge strategy, and combines all rows into a single dataset. It preserves compatible values whenever possible, reports structural differences, and generates a clean CSV that is immediately ready for review, export, or further processing.
Use cases
Combine monthly exports
Join several extracts that share the same column structure.
Merge related sources
Combine files with partially different columns by using union mode.
Prepare global analysis
Create one dataset before sorting, filtering, or deduplicating it.
Guide
How to use this tool
- 1
Add the data
Paste the CSV or provide the information required by the tool.
- 2
Configure processing
Choose the columns, rules, or options that match your objective.
- 3
Review the result
Check the report, then copy or download the generated data.
Tips and best practices
- Keep a copy of the source file before applying an important transformation.
- Check the delimiter and header-row setting before running the operation.
- All processing stays in your browser and no CSV file is uploaded.
Frequently asked questions
Are my CSV data uploaded?
No. Parsing, comparisons, and transformations are executed locally in your browser.
Are quoted fields supported?
Yes. The CSV engine supports delimiters inside quoted fields and multiline quoted content.
Can I download the result?
Yes. When a new CSV is produced, it can be copied or downloaded directly from the page.
Was this tool useful?
Read next
GuideBest practicesBeginner
Merge CSV or Excel files without misaligning columns
Learn how to align headers, verify schemas and combine several CSV or Excel files while avoiding duplicated or shifted columns.
29 August 20262 minRead
GuideBest practicesBeginner
Split a CSV or Excel table into smaller files
Discover when to split a large table by row count or by a column value, and how to preserve a useful structure in every output file.
29 August 20261 minRead
GuideBest practicesBeginner
Compare two CSV or Excel files and identify the differences
Learn how to compare two versions of a table using a stable key and distinguish added, removed and modified records.
29 August 20262 minRead
GuideBest practicesBeginner
Data and tables: understanding CSV, Excel, JSON and dataset structure
Learn how tabular data is structured, how CSV, Excel, JSON and TSV differ, and how to choose the right format before cleaning, converting or automating a workflow.
29 August 20263 minRead
Recommended workflow
Continue your processing
Discover tools that naturally fit before, after, or alongside this one.
Complementary tools
Data & spreadsheets
CSV Splitter
Split a CSV file into smaller files using the size or groups you choose.
100% local
Use this toolData & spreadsheets
Merge Excel or CSV files
Merge multiple Excel or CSV files into one table with automatic column alignment.
100% localFeatured
Use this toolData & spreadsheets
CSV Deduplicator
Remove duplicate CSV rows using the columns you choose as matching criteria.
100% local
Use this tool