Free CSV merger
Merge CSV Files Into One
Combine two or more CSV files in your browser. Match columns by name even when their order changes, keep headers once, preview your results, and download a single CSV.
Combine Your CSV Files
Choose two or more files, match their columns, then download a single CSV.
Files to merge
0 files selectedFiles are combined in the order shown. Use the arrows to move a file up or down.
Choose at least two CSV files to begin.
Merge options
Files can have columns in different orders. Each column name must be unique, and uppercase and lowercase letters are treated differently.
Merged CSV Preview
Showing up to 20 data rows and 12 columns. The download contains the full result.
Your original files are not changed. This tool puts rows together; it does not combine records that share an ID. CSV cells beginning with =, +, - or @ may be treated as formulas when opened in spreadsheet software.
How Do I Merge CSV Files Into One?
To merge multiple CSV files into one, choose two or more files above and check the order. Keep Match columns: By column name to align fields even if the column order differs between files. Select how to handle missing columns, then click Merge CSV Files. The merger appends the data rows, includes the header only once, and lets you preview the result before downloading.
How to Merge Multiple CSV Files Online
Select CSV files
Choose two to twenty .csv or .tsv files, or use the sample files. Move a file up or down to change the order in your merged CSV.
Choose how to match columns
Keep the default column-name matching for files with headings. Combine all columns if some files have additional fields, or require matching columns for stricter checks.
Preview and download
Click Merge CSV Files. Review the merged row count, table preview and any warnings, then download a complete UTF-8 CSV.
Merge CSV Files With the Same Headers in a Different Order
The example below uses two CSV files containing the same fields but different column orders. The merger matches each column name so names and cities do not get mixed up.
Combined result: one header, four data rows
id,name,city
00127,Alice,New York
00128,Bob,Chicago
00129,Emma,Seattle
00130,John,AustinCombine CSV Files With Different Column Names
If the files do not share every heading, Combine all columns collects the distinct column names from every file. When a row does not have a value for a column, the output cell is left empty. The original file order determines the output row order; the first file's columns appear first.
First file
id,name
001,Alice
002,BobSecond file
id,name,amount
003,Emma,100
004,John,200Combined result:
id,name,amount
001,Alice,
002,Bob,
003,Emma,100
004,John,200If every file should contain exactly the same column names, select Require matching columns. The tool then stops and identifies a file with a different column set instead of silently moving data into the wrong field. Column-name matching is case-sensitive, so ID and id are different.
Merge CSV Files With Matching Headers or Without Headers
| Option | When to choose it | Result |
|---|---|---|
| First row contains column names | Files start with a header such as id,name | Only one header row is written |
| By column name (default) | Columns may appear in different orders | Values follow the matching heading |
| By column position | Files have equivalent data without consistent headings | First column joins first column, second joins second |
| Combine all columns | Some files have extra or missing fields | All columns retained, missing cells empty |
| Require matching columns | You want to catch inconsistent file layouts | Stops if column names or column counts differ |
| Remove identical data rows | Files may contain repeated entries | Removes rows with identical values after matching columns |
| Add source filename column | You need to know where each row came from | Adds a source_file column showing the original file name |
File names are included only if you choose the source filename option. The merger keeps cell values as text, including leading zeros. Duplicate removal compares full data rows after columns have been aligned; it does not match people or orders by ID.
Combine Rows or Match Records by ID?
Combine rows (this tool)
Put records from one file below records from another. For example, combine January and February customer lists into one table with the same column headings.
Use for: monthly exports, logs, reports and lists with similar fields.
Match records by ID (not available here)
Match a person or order from one table to the same ID in another, then add fields beside the matching row. That requires matching records using a shared value, such as a customer ID.
Use for: relating different datasets by customer ID, product ID or email.
“By column name” puts values under the correct headings. It does not combine separate records that share an ID.
Which CSV Merge Settings Should I Use?
Use these examples to choose the right options before you combine CSV files. If you are unsure, start with the default settings and inspect the preview before downloading.
| Your files | Recommended settings | Why |
|---|---|---|
| Monthly reports with the same columns | Headers on · By column name · Require matching columns | Appends the reports while catching a missing or unexpected heading. |
| Exports whose columns appear in different orders | Headers on · By column name | Matches values to headings instead of assuming the first column means the same thing everywhere. |
| Reports with some extra or missing columns | Headers on · By column name · Combine all columns | Keeps all distinct headings and fills missing cells with blanks. |
| CSV or TSV files with no header row | Headers off · By column position | Appends values based on their position, without treating the first data row as a heading. |
| Overlapping exports containing exact repeated rows | Remove identical data rows | Keeps the first occurrence of each identical full row; it does not choose the latest record for an ID. |
| Files from several teams or periods | Add source filename column | Shows which file each retained row came from; useful when checking the combined result. |
How to Merge CSV Files Without Losing or Mixing Up Data
Check the headings first
customer_id and Customer_ID are different headings. Rename inconsistent columns in the source files before merging if they represent the same data.
Decide what counts as a duplicate
Exact-row removal is useful for repeat exports, but two orders with the same customer ID and different amounts are both retained. Review such records separately if you want to remove duplicates based on customer ID.
Check text, separators and the download
For non-English text, choose the correct input encoding if the preview looks garbled. For Excel, try the UTF-8 BOM download option; import ID columns as Text to keep leading zeros.
The merger keeps cell values as written. If CSV cells begin with formula-like characters such as =, opening the downloaded CSV in a spreadsheet app may interpret them as formulas. Review files from untrusted sources before opening them in Excel.
When Is Combining Multiple CSV Files Useful?
Combine monthly sales exports
Append January, February and March transactions into one file for reporting. Use source filenames if you need to trace a row back to its month.
Consolidate survey responses
Combine responses exported in separate batches. Choose Combine all columns if newer surveys include additional questions; unanswered fields stay blank.
Put event logs together
Combine log files with the same headings into one CSV. Rows stay in the order you choose; the tool does not automatically sort entries by date or time.
Prepare a single file for analysis
Bring together similarly structured CSV exports before using a spreadsheet, charting tool or data analysis workflow. Check the preview and download the full combined CSV.
Features of Our Free Online CSV Merger
Combine Multiple CSV Files
Merge up to twenty CSV or TSV files without uploading them. Choose the file order before creating the result.
Match Columns by Name
Keep values in the correct fields even when the files list those fields in different orders. Check missing and extra columns.
Clean Up Your Combined Data
Optionally remove duplicate data rows, skip empty rows or add a source filename column so you can see which file each row came from.
Preview and Download
Check the row count and preview, then download the complete result as UTF-8 CSV, or UTF-8 with BOM if you plan to open it in Excel.
How to Merge CSV Files in Excel
If your CSV files are already in the same folder and you prefer Excel, you can combine them through Power Query rather than copying data manually.
Put files in one folder
Save the CSV files you want to combine in a folder. Make sure their column names represent the same fields.
Import the folder
In supported desktop Excel versions, choose Data → Get Data → From File → From Folder, then select the folder.
Combine and check
Use Combine & Transform Data, check the detected headers and field types, then load the combined table into Excel.
Excel menus vary by version. If you just need one CSV download, the browser tool above works without setting up an Excel query.
Supported CSV Formats and File Limits
| Input | 2–20 CSV or TSV files |
|---|---|
| File size | Up to 10 MB per file and 30 MB combined |
| Maximum merged rows | 100,000 data rows before removing any duplicates |
| Maximum columns | 100 including the optional source-file column |
| Maximum cells | 1,000,000 merged data cells |
| Maximum output | 50 MB |
| Input delimiters | Comma, semicolon, tab and pipe (automatically detected per file or set manually) |
| Input encoding | UTF-8, UTF-8 BOM, UTF-16 BOM; manual UTF-16 LE, Windows-1252 and ISO-8859-1 |
| Output | Comma-separated CSV, UTF-8 or UTF-8 with BOM |
| Preview | Up to 20 data rows and 12 columns; your download contains all merged data |
Common Problems When Merging CSV Files
| Problem | Likely cause | What to do |
|---|---|---|
| Rows appear in the wrong columns | Files use a different column order | Choose By column name and verify the headers |
| A file has repeated or blank column names | There is no unique heading to match | Rename those headings or choose By column position |
| Different columns block the merge | Require matching columns is selected | Choose Combine all columns to keep extra fields |
| Everything appears in one column | The separator was detected incorrectly | Select Comma, Semicolon, Tab or Pipe manually |
| Text appears garbled | The source file uses another encoding | Choose the matching File encoding option |
| Duplicate entries remain | The values are not identical, or duplicate removal is off | Enable Remove identical data rows; it matches complete rows, not IDs |
| Values such as 00127 change in Excel | Excel infers numeric types when opening CSV | Import that column as Text in Excel; the merger preserves the original cell text |
| The file is too large | It exceeds the file, row, column, cell or output limit | Choose fewer files or split the data into smaller groups |
Merge CSV Files Without Uploading Them
Your selected files are read, combined, previewed and downloaded locally in the browser. Your CSV contents, file names and column headings are not uploaded or included in usage statistics. We may count general actions, such as trying the sample or clicking Download. The original files stay unchanged.
Merge CSV Files Frequently Asked Questions
How do I merge multiple CSV files into one?
Choose two or more CSV files above, review their order and merge options, then click Merge CSV Files. Check the preview before downloading your combined CSV.
Can I merge CSV files online for free?
Yes. The CSV merger is free, requires no account, and processes your selected files locally in your browser. No files are uploaded to a server.
Can I merge CSV files with the same headers?
Yes. Leave First row contains column names on. The output has one header row followed by the data from each file in the selected order.
What happens if my CSV files have different columns?
By default, Combine all columns includes every distinct column name and leaves missing values blank. You can instead select Require matching columns to stop when the column sets differ.
What if the same columns appear in a different order?
With By column name selected, values are matched by heading rather than position. Leading and trailing spaces in headings are ignored, but uppercase and lowercase letters count as different names. If a heading is empty or repeated, rename it or match columns by position.
Can I remove duplicate rows while merging?
Yes. Select Remove identical data rows. The tool removes rows that contain exactly the same values after matching columns, including repeats within one file. Differences in letter case or spaces are preserved.
Can I track which CSV file each row came from?
Yes. Enable Add source filename column to include the original filename beside each merged row. This also adds a header row when merging CSVs without column names.
Does merging CSV files also join records by ID?
No. This tool appends data rows vertically. It does not match records using an ID or place matching details side by side.
Can I merge CSV files without column headings?
Yes. Turn off First row contains column names. Data will be combined by column position, and the output will not have a header unless the source filename option is on.
Does the merger sort records by date or ID?
No. Rows follow the order of the selected files, and rows within each file keep their original order. Sort the downloaded data separately if needed.
Can I merge CSV files with different delimiters?
Yes. Automatic delimiter detection checks each file separately for commas, semicolons, tabs or pipes. You can also choose one delimiter manually if automatic detection is incorrect.
Will merging CSV files preserve leading zeros?
Yes. The merger treats values such as 00127 as text. Some spreadsheet programs may reinterpret them when opening a CSV, so import ID columns as Text if necessary.
Are the files uploaded to a server?
No. Your files are processed in your browser, not uploaded to our server. We do not include file names, headings or CSV contents in usage statistics.
More CSV Tools and Guides
Ready to merge your CSV files?
Choose two files or try the sample, then download a single combined CSV.