Join files on a key, trim, concatenate, fix dates, filter and more, in the order you choose.
Data Transformation lets you reshape a file with a list of steps instead of formulas. Join two files on a key with an inner, left, right or full join, trim spaces, concatenate or split columns, change date formats, change case, find and replace, filter, sort, remove duplicates and fill empty cells. See the result straight away, then download it or send it to another tool. Every step is recorded in Data Lineage.
Load a file (and a second one to join)
Add the transformations you want
Check the result and download
Tips
Remove empty values drops rows with empty cells, or columns that are completely empty. Choose whether the text null, NaN and N/A counts as empty.
Reorder columns: drag a column, or use the arrows to send it to the start or end.
Joins match keys ignoring case and spaces.
Add Trim spaces before a join if keys have stray spaces.
How do I move a column to the first position in a CSV?
Add a Reorder columns step and click the move to start button next to the column, or drag it to the left.
Does it work on a phone or tablet?
Yes. Dragging needs a mouse, so on touch screens use the buttons that send a column to the start or the end.
Do later steps use the new order?
Yes. Every step after it, and the download, use the new column order.
Can I join two files or combine columns?
Yes. Data Transformation lets you join two CSV or Excel files on a key (inner, left, right or full), and trim spaces, concatenate columns, change case, find and replace, split, rename, filter, sort, remove duplicates and fill empty cells. You choose the steps, check the result and download it. Your files stay in your browser.
Which transformations are available?
Join with a second file (inner, left, right or full), trim spaces, concatenate columns, change date formats, change text case, find and replace, split a column, rename or remove columns, filter rows, remove duplicates, sort and fill empty cells. Steps run from top to bottom and you can reorder them.
Can I change the date format of a column?
Yes. Add a Change date format step, pick the column and the new format, such as 2026-03-09, 09/03/2026 or March 9, 2026. It reads many layouts, Excel date numbers and unix timestamps, and can also give only the year, month, weekday or quarter. If 03/04/2026 is unclear, you choose day first or month first.
Is Data Transformation a VLOOKUP alternative?
For lookups between two files, yes. A join adds the matching columns from the second file to every row of the first, with no formulas. Keys are matched ignoring case and extra spaces.
Related pages
Data Transformation: Join, Trim, Concatenate: Join two CSV or Excel files on a key, trim spaces, concatenate columns, filter, sort and more. Pick your steps and download the result. Free, in your browser.
Delete Columns from a CSV File: Remove one or more columns from a CSV or Excel file and download the result. Free, in your browser, and your file is never uploaded.
Remove Empty Rows and Columns from CSV: Remove rows with empty cells, rows that are completely empty, or columns with no values from a CSV or Excel file. Free, in your browser.
Find and Replace in a CSV File: Find and replace text in a column of a CSV or Excel file, then download the result. Free, in your browser, and nothing is uploaded.
Change Date Format in a CSV File: Change the date format of a column in a CSV or Excel file, for example 09/03/2026 to 2026-03-09, or get only the year or month. Free, in your browser.
Convert Excel Date Numbers to Dates: Turn Excel date numbers such as 46090 and unix timestamps into readable dates in a CSV or Excel file. Free, and your file stays in your browser.
Join Two CSV Files on a Key: Join two CSV or Excel files on a key column with an inner, left, right or full join. Free, and your files stay in your browser.
Merge CSV Files by a Common Column: Merge two CSV files into one by matching a common column such as id or email. Choose inner, left, right or full. Free, in your browser.