- Home
- →
- Data Tools
- →
- CSV Merger
CSV Merger Tool [2025]
Merge multiple CSV files with powerful options for appending, joining, and data handling - all in your browser.
Upload CSV Files
Select or drag & drop CSV or TXT files. Ensure files are plain text and use common delimiters like comma, semicolon, or tab.
Merge Options
Key Features
- Merge multiple CSV files with two powerful methods: append (stack vertically) or join (combine based on a common field).
- Configure how empty values, whitespace, and duplicates are handled during the merge process.
- Preview your data at every step of the process to ensure accurate results.
- All processing happens in your browser - your data never leaves your computer.
- Customize output options including delimiter selection for maximum compatibility.
- Support for large CSV files up to 10MB each.
- No account required - completely free to use with no limits.
Merge Methods Explained
Append Mode
Stack files vertically, one after another. This is ideal when you have similar CSV files that you want to combine into one larger dataset. For example:
File 1:
name,age,city John,30,New York Alice,25,Boston
File 2:
name,age,city Bob,45,Chicago Carol,35,Seattle
Result (Append):
name,age,city John,30,New York Alice,25,Boston Bob,45,Chicago Carol,35,Seattle
Join Mode
Merge files based on a common field (join key). This is useful when you have related data spread across multiple files. For example:
File 1 (Customer Data):
customer_id,name,email 1001,John Smith,john@example.com 1002,Jane Doe,jane@example.com
File 2 (Order Data):
customer_id,order_total,date 1001,125.50,2025-01-15 1002,89.99,2025-01-20
Result (Join on customer_id):
customer_id,name,email,order_total,date 1001,John Smith,john@example.com,125.50,2025-01-15 1002,Jane Doe,jane@example.com,89.99,2025-01-20
Common Use Cases
Data Analysis
- • Combine monthly reports
- • Merge datasets from different sources
- • Consolidate survey responses
- • Prepare data for visualization
Business Operations
- • Combine customer databases
- • Join product and pricing data
- • Merge inventory listings
- • Consolidate financial records
Data Migration
- • Prepare data for new systems
- • Normalize data structures
- • Combine legacy data files
- • Clean and restructure datasets
Frequently Asked Questions
Is my data secure when using this tool?
Yes, absolutely. All processing happens entirely in your browser. Your CSV files are never uploaded to any server, ensuring that your sensitive data remains private and secure on your local device.
How should I choose between append and join modes?
Use append mode when you want to stack similar files one after another (like combining monthly reports). Use join mode when you have related data across different files that share a common identifier (like customer data and order data that both have customer IDs).
What happens if my CSV files have different columns?
The tool handles this intelligently. In append mode, you can choose to include all columns from all files (with empty values where appropriate) or use only columns from the first file. In join mode, you can merge files based on a common field while retaining all other columns.
How large can my CSV files be?
The tool supports CSV files up to 10MB each. For very large files, processing may take a bit longer depending on your device's capabilities, but all operations remain browser-based to ensure your data privacy and keep server costs low.
Comments
No comments yet
Be the first to share your thoughts! Your feedback helps us improve our tools and inspires other users.
More Data Tools
ASCII to CSV Converter
Convert ASCII table format to CSV files
Base32 Decoder/Encoder
Decode or encode Base32 data
Base58 Decoder/Encoder
Decode or encode Base58 data
Base58 to Hexadecimal Converter
Convert Base64 encode to hexadecimal format
Base64 Decoder/Encoder
Decode or encode Base64 data
Base64 to ASCII Converter
Convert Base64 encode to ASCII format
Base64 to Binary Converter
Convert Base64 encode to binary format
Base64 to CSV Converter
Convert Base64 encode to CSV files
Base64 to Decimal Converter
Convert Base64 encode to decimal format
Base64 to Hexadecimal Converter
Convert Base64 encode to hexadecimal format
Base91 Decoder/Encoder
Decode or encode Base91 data
Binary to Base64 Converter
Convert binary to Base64
Binary to Decimal Converter
Convert binary to decimal
Binary to Gray Code Converter
Convert binary to gray code
Binary to Hexadecimal Converter
Convert binary to hexadecimal
Binary to Octal Converter
Convert binary to octal
CSV to ARFF Converter
Convert CSV files to ARFF format for ML tasks
CSV to ASCII Converter
Convert CSV files to ASCII tables
CSV to Base64 Converter
Convert CSV files to Base64 format
CSV to DOC (Word) Converter
Convert CSV files to DOC format for MS Word
CSV to HTML Converter
Convert CSV files to HTML tables and code
CSV to JPG Converter
Convert CSV files to JPG images
CSV to JSON Converter
Convert CSV files to JSON format
CSV to Markdown Converter
Convert CSV files to Markdown tables
CSV to SQL Converter
Convert CSV files to SQL code
CSV to TSV Converter
Convert CSV files to TSV format
CSV to XLSX Converter
Convert CSV files to XLSX (Excel) format
CSV to XML Converter
Convert CSV files to XML format
CSV to XML Converter
Convert CSV files to YAML format
Decimal to ASCII Converter
Convert decimal to ASCII
Decimal to Binary Converter
Convert decimal to binary
Decimal to Gray Code Converter
Convert decimal to gray code
Decimal to Hexadecimal Converter
Convert decimal to hex
Decimal to Octal Converter
Convert decimal to octal
Decimal to Roman Converter
Convert decimal to Roman numerals
Gray Code to Binary Converter
Convert gray code to binary
Gray Code to Decimal Converter
Convert gray code to decimal
Gray Code to Hexadecimal Converter
Convert gray code to hexadecimal
Gray Code to Octal Converter
Convert gray code to octal
Hexadecimal to Base58 Converter
Convert hexadecimal to Base58 encoding
Hexadecimal to Binary Converter
Convert hexadecimal to binary
Hexadecimal to Decimal Converter
Convert hexadecimal to decimal
Hexadecimal to Gray Code Converter
Convert hexadecimal to gray code
Hexadecimal to Octal Converter
Convert hexadecimal to octal
JSON to CSV Converter
Convert JSON code to comma-separated value (CSV) files
JSON to HTML Converter
Convert JSON code to HTML table code
JSON to Markdown Converter
Convert JSON code to Markdown tables
JSON to SQL Converter
Convert JSON code to SQL
JSON to Table Converter
Convert JSON code to a table
JSON to TSV Converter
Convert JSON code to TSV
JSON to XLSX Converter
Convert JSON code to XLSX (Excel)
Markdown to CSV Converter
Convert Markdown tables to CSV files
Markdown to JSON Converter
Convert Markdown tables to JSON code
Markdown to XLSX Converter
Convert Markdown tables to XLSX (Excel) files
Markdown to XML Converter
Convert Markdown tables to XML code
Markdown to YAML Converter
Convert Markdown tables to YAML code
Number Base Converter
Convert between decimal, binary, hex, and octal
Octal to Binary Converter
Convert octal to binary
Octal to Decimal Converter
Convert octal to decimal
Octal to Gray Code Converter
Convert octal to gray code
Octal to Hexadecimal Converter
Convert octal to hexadecimal
Protobuf to CSV Converter
Convert Protobuf code to CSV files
Punycode to Unicode Converter
Convert punycode to unicode
SQL to CSV Converter
Convert SQL code to CSV files
SQL to HTML Converter
Convert SQL code to HTML tables
SQL to JSON Converter
Convert SQL code to JSON
SQL to Table Converter
Convert SQL code to a table
SQL to XLSX Converter
Convert SQL code to XLSX file
SQL to XML Converter
Convert SQL code to XML
SQL to YAML Converter
Convert SQL code to YAML
TSV to CSV Converter
Convert TSV format to CSV file
TSV to JSON Converter
Convert TSV format to JSON
TSV to SQL Converter
Convert TSV format to SQL code
TSV to XLSX Converter
Convert TSV format to Excel file
TSV to XML Converter
Convert TSV format to XML
TSV to YAML Converter
Convert TSV format to YAML
Unicode to Punycode Converter
Convert unicode to punycode
URL Encoder/Decoder
Encode and decode URLs
XLSX to CSV Converter
Convert XLSX to CSV file format
XLSX to HTML Table Converter
Convert XLSX files to HTML tables
XLSX to JSON Converter
Convert XLSX files to JSON
XLSX to Markdown Converter
Convert XLSX files to Markdown tables
XLSX to TSV Converter
Convert XLSX to TSV file format
XLSX to XML Converter
Convert XLSX files to XML
XLSX to YAML Converter
Convert XLSX files to YAML
XML to CSV Converter
Convert XML code to CSV file format
XML to Markdown Converter
Convert XML code to Markdown tables
XML to SQL Converter
Convert XML to a SQL
XML to Table Converter
Convert XML to a table
XML to TSV Converter
Convert XML to a TSV file
XML to XLSX Converter
Convert XML to a XLSX file
YAML Converter
Convert between YAML and other formats
YAML to CSV Converter
Convert YAML to CSV file format
YAML to Markdown Converter
Convert YAML code to Markdown tables
YAML to XLSX Converter
Convert YAML to XLSX file format