Best CSV Diff Tool to compare CSV files for differences
What are the benefits of choosing xlCompare as your CSV diff tool
xlCompare is a good choice if you need to compare CSV files on the daily basis. Let's look into the advantages you are getting if you choose xlCompare as you diff tool for CSV files

Simplicity
xlCompare is very easy to use and has intuitive interface, build in the close interaction with our customers. You don't need to spend your time learning the tool. Just install and use. In case of any questions our technical stuff will be happy to provide you with online demo of the product.

Efficiency
We don't give you a CSV comparison tool, we are saving your working time and increasing productivity. This is primary aspect of xlCompare.
In the modern world we are greatly overloaded, so working time is a critical resource.
xlCompare works on thousands of computers around the world and is chosen by leading companies.
You should not be expert in Excel to use this tool
xlCompare is a tool for all common Excel users. If you are an Excel expert or advanced user, probably you don't need a diff tool for Excel files at all. You can do everything yourself. But xlCompare is an option for common Excel users that are not familiar with Conditional Formatting, VLOOKUP function, Visual Basic for Automation programming language and so on.
Privacy
Your files are not uploaded to the web. They are compared directly on your computer.
Compare files by Key
Database tables are often stored in the CSV files and Excel worksheets. Records that were exported from the database usually saved and transmitted as CSV.
xlCompare allows you to define primary key columns and heading rows in your tables and compare them as structured data, not like a usual spreadsheet model with formulas and calculations.
Lifetime License = No Future Payments
Lifetime license is an important advantage. You are getting a software that will work for you forever. xlCompare is not a subscription, so there will be no future payments.
Your license gives you ability to upgrade the software to all future versions of the software for free.
xlCompare makes complex things simple!
How to find differences in two CSV files
xlCompare is a easy way to find differences in two CSV files and highlight them with color. Just in a few clicks you will have your job done. And this is extremely simple.
Open your CSV files in xlCompare application
How to open two CSV files in xlCompare? Just drop them from the Windows explorer into the xlCompare window. The software will open them for you.

Setup Primary Keys
Once you have your files opened, you need to make sure that Primary Keys are configured properly. This is highly important option to get the accurate results.
Each Primary Key column is marked with Key icon in the heading and highlighted with color.
If you think that you need another selection for your table, than the default one - do the right click on the column heading and set or unset the Key flag.
If you mark your column as Standard column - it will not be considered as Key.

Get the Results
Use Compare Sheets command on the Ribbon.

It brings you Comparison Wizard window that contains summary of the data to be compared. After your Primary Keys are selected, just close it by pressing the Compare button and proceed to Comparison Report.

Working with Comparison Report
xlCompare provides you with a comprehensive color-coded comparison report. All the differences found between two CSV files are highlighted with color. You will easily identify them among other cells.

Changed cell value
Two changed cells are highlighted with Orange fill color.
For the numeric values xlCompare adds tendency icon that indicates increase or decrease of the value.
All identical rows with equal or changed cells are aligned on the worksheets one versus one.

Added and Deleted rows
All rows that are not identified in the other worksheet are highlighted with green color in the left file and with a red color in the right file.
Unique Rows (this term is used for added and deleted rows) doesn't have a corresponding row, so xlCompare inserts empty space into the corresponding worksheet to keep the alignment for the matching rows.

Detailed information on the changes
Move your mouse over the orange cell and xlCompare will give you detailed information about what was changed in this cell in the Tooltip window.
This is easy and convenient way to get the details of the comparison.

Filter records in CSV files with xlCompare
xlCompare gives you several options on how to quickly filter your data in the worksheet. All of there commands are present on the Home tab of the Ribbon.

All cells
This is the default selection. No filtering is applied, all cells on the worksheets are visible.
Matching Rows
xlCompare displays only rows with identical cells.

Updated Rows
xlCompare display only rows that contains at least one updated cell. These rows have orange background in the heading.

Unique Rows
This filter shows mismatched rows on two worksheets. So, if you apply this command xlCompare shows you only green and red rows in the compared CSV files. This is usually called - difference between the CSV files.

Compare only specific segments of data in CSV files
xlCompare supports auto filter feature that is present in Excel application. If your CSV file is opened in xlCompare, it is automatically formatted as table and xlCompare applies auto filter to this table.
So, you can filter your data in the comparison report by specific data segments.
For example, if you need to compare sales made by your partners in specific marketing segments in USA, just select appropriate filters like on the image below.
xlCompare will show you records that belongs to this segment only.

Highlight differences in CSV files
How to highlight changed cells permanently in the file? Apply Mark Changes with Color command on the Ribbon.
It applies color formatting to every changed cell and every unique row.
Please note, that CSV file doesn't allow to keep the formatting options, so you need to save it as XLSX file by clicking on the Save As button.

Extract data from the CSV file into Excel workbook
You've filtered your data by specific criteria. How to get these records including color formatting to be saved in the other file?
Use Save | Only Visible Rows command from the right click menu on the worksheet.
xlCompare will save visible data in the XLSX file on disk. This is easy way to export block of the worksheet and send it by email to your colleague.

Get Rid of Mismatching Rows in CSV file
How to clean your CSV file from the redundant rows, that are not present in the worksheet.
First you need to compare your CSV files for differences in xlCompare.
Apply Unique Rows filter to get the mismatching rows on your screen.
Select all the rows on one side and apply the Delete command from the right click menu.
xlCompare will remove rows from the worksheet.
Now your sheet is clean from the mismatching rows.

Merge(combine) two CSV files into one
xlCompare is a tool that gives you easy method to populate one CSV file with records from the other file.
Look into Merge tab on the ribbon
Set of the commands allows to copy data from one worksheet to another are located on this atb.

If you need to add all the mismatching rows from the left file into the right one - apply Insert Rows From Left command
All the green rows are moved into the right file in one click. Easy and convenient.
Similar command Update Cells from Left copies all the updated cells from the left file into the right one. You are getting your CSV file updated just in one click.

Compare three CSV files for diffs and matches
What to do if you have 3 CSV files you need compare at once. How to find rows that were updated in all CSV files. Or how to extract matching rows - rows that are present in all 3 lists of data.
Apply the 3-File option on the Home tab on the Ribbon.
xlCompare gives you additional panel for the third file. Just open your third file in this panel and get the result.
At no extra efforts you are getting results for such complex task.
In this mode xlCompare also allows you to filter data by specific criteria, filter changed and mismatching records, save visible portion of data on the other worksheet and so on.
Three file comparison for the CSV files is an important benefit that is present in the xlCompare.

CUSTOMER FEEDBACK: Very nice software
Very nice your software, the 3 ways blowed my mind out, I did a 2h job in 10 minutes (I looked 5 sec at my screen without moving because I was so surprised).
Olivier Regout
CONCLUSION: Choosing best CSV diff tool
So, which CSV diff tool is the best? How to make a decision on choosing best diff tool for CSV files.
Benefits of the xlCompare are already discussed above, there is no sense to repeat. But we would like to give you a short list of the proc and cons of the software.
Proc
xlCompare is a easy to use application that perfectly compares and merges CSV files. This tool is a real timesaver in many cases. Armed with xlCompare you can do complex tasks in a seconds.
Cons
Possible xlCompare has one minus - this tool is not free. You can use it during evaluation period, but after it expires you need to order a license.

Why xlCompare is an ultimate tool
xlCompare can be used in various cases that requires spreadsheet comparison. Following advantages makes this tool ultimate utility for CSV file comparison nd merging:
Easy to use
Application has very clear and native interface, that is very similar to Microsoft Excel.
Efficiency
xlCompare makes you efficient in your daily work with Excel. This saves you a lot of efforts and working time.
Clear results
You are getting clear and easy to understand comparison results. You can see examples on the screenshots above.
Reasonable price
Actual price of xlCompare is amount of time spent to spreadsheet comparison multiplied by your hourly rate. So, the application has reasonable price in comparison with other tools on the market.
Lifetime license
xlCompare is sold as a lifetime license. You don't need to pay more for this tool. License includes upgrades to all future versions of the xlCompare and support.
Now we have version 11 on the website. If you order it now, you will be able to upgrade it to xlCompare 12, xlCompare 15 and so on.
You never lose your license.
Alternate methods of comparing CSV files
Off course there are several other methods that allows to compare CSV files for differences. If your files are relatively simple, or you are doing this very rarely, probably you can use other method. Some of them are briefly described above.
Compare two CSV files with Visual Basic Macro
Visual Basic for Applications (VBA) is very powerful feature that is present in Excel application. If you know programming, you can use it to implement the comparison and highlighting algorithm for your CSV files. Also, you can look for the macro on the web. There are a lot of free examples.
But this method doesn't allow you use some advanced features that are present in xlCompare:
Ignore specific characters
Numeric accuracy (ignore minor changed in your numbers)
Also, you need to spend you time by creating and adjusting the macro, while xlCompare gives you immediate results.
If you value your time, you will make a choice!
Compare CSV files on-line
There are several websites that offer free on-line comparison for CSV files. This is a perfect alternative to xlCompare and to Visual Basic for Applications.
Again, if you need to just find the difference in two CSV files, you can use this method. It will work well you for.
Why doesn't Spreadsheet Tools offer free on-line comparison for CSV files?
Our company provides a professional and feature rich solution that allows not only to point you to the difference, but to analyze the data and save presentation report for the comparison.
At this moment this can be done only in a form of desktop application.
Download CSV comparison tool
Here is a direct link you can use to download CSV file comparison tool.
If you have any questions on the product or you need a short on-line demo of the product, please contact us.
I have a question about xlCompare
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ADDITIONAL RESOURCES
Get more information about comparing Excel spreadsheets and CSV files for differences. Alternatives to xlCompare and other useful information.