Merge, join and clean spreadsheets without uploading them
Combine a folder of CSV exports, match two Excel files on an ID, strip the duplicates, then save as CSV, Excel or JSON. FileMixer does it inside your browser, so customer lists and payroll files stay on your computer.
Pick a tool
Each one opens CSV, Excel (.xlsx and .xls), ODS, TSV and JSON files, shows you the result before you download, and saves to whichever format you need.
Join two files on a column
VLOOKUP for the whole sheet. Bring prices, names or emails from one file into another wherever an ID matches, and see which rows didn't.
Join two files →Merge files
Stack many CSV or Excel files into one, with columns matched by name.
Merge files →Remove duplicates
Drop repeated rows, judged on every column or just the email.
Remove duplicates →Split a file
By row count, into equal parts, or one file per region, rep or store.
Split a file →Clean columns
Trim spaces, remove invisible characters and empty rows, rename and reorder.
Clean columns →Convert
CSV, Excel and JSON, in any direction, with leading zeros and accents kept.
Built for files you can't send anywhere
Your files stay put
The tools read files with your browser's own file reader and do the work in this tab. The site's security policy blocks the page from sending data out, so even a bug couldn't upload your file.
Fast on big exports
Files are read in a background thread, so the page stays responsive. A 50,000-row CSV opens in a second or two, and you see a preview before anything is saved.
Output Excel opens cleanly
ZIP codes keep their leading zeros, long IDs don't turn into 1.23E+15, and CSVs carry a UTF-8 marker so names like “Zoë” and “José” survive.
Guides
Short, practical how-tos for the spreadsheet jobs that come up every week.
How to merge Excel files into one
Three ways, from copy and paste to a repeatable setup, and how to handle columns that don't line up.
How to do a VLOOKUP without Excel
Match two lists on an ID and bring columns across, and why some rows refuse to match.
Open a CSV in Excel without losing leading zeros
Stop Excel from eating ZIP codes, mangling long numbers and garbling accents.
Need this done for you, or every week?
Web Landscapes can clean and combine your files for you, or set it up to run on its own: a monthly report merged from branch files, a price list matched to a supplier feed. Tell us what you have and we'll quote it.