Append CSV & Excel files — stack rows from multiple files
e.g. stack January's and February's sales reports into one file.
Looking to merge files by shared columns instead? Try Merge.
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How to append (stack) CSV & Excel files
- 1
Add the files to stack
Drop in two or more CSV, Excel (.xlsx, .xls), or TSV files that share the same columns — monthly reports, regional exports, log batches. They are read in your browser; nothing is uploaded.
- 2
Check how columns line up
Tabularly aligns columns by name, so files with the same headers in a different order still stack correctly. Columns missing from one file are filled with blanks.
- 3
Stack and download
The rows are concatenated into one table in the order you added the files. Preview it, optionally remove duplicates, and download as CSV or Excel.
Stacking files with the same columns
Appending stacks tables vertically: the rows of each file are placed below the previous one to make a single longer table with the same columns. It is what you reach for when data arrives split into pieces of the same shape — twelve monthly exports, one file per region, daily log batches — and you need them as one. This is also called stack, concatenate, union, or “Append Queries” in Power Query and Power BI.
It is the opposite axis from merging: merge joins files side by side on a key to add columns; append puts them end to end to add rows. Tabularly aligns columns by name, so files whose headers are in a different order still line up, and a column missing from one file is filled with blanks rather than shifting your data.
Because stacking overlapping exports often produces repeats, you can remove duplicates on the combined result in the same flow — a common one-two for consolidating reports cleanly. The rows keep the order in which you added the files.
Everything runs in your browser, so your data never leaves your device — unlike tools that upload your spreadsheets. The free tier combines a handful of files up to about 10 MB each; Pro handles larger files and bigger batches.
Frequently asked questions
What is the difference between append and merge? +
Append stacks files vertically — the rows of one file go below another, producing more rows with the same columns. Merge joins files horizontally — it matches rows on a shared key and adds more columns. Use append for "same shape, more rows" and merge for "combine related columns".
Do the files need identical columns? +
They should share the same column structure. Tabularly aligns columns by name (order does not matter), and where a column is missing from one file the cells are left blank, so minor differences are handled gracefully.
Is this the same as concatenate / union / "Append Queries"? +
Yes — stack, concatenate (concat), union, and Power Query / Power BI "Append Queries" all describe this same vertical combine. Here it takes a few clicks with no setup.
How many files can I append at once? +
Several at a time. The free tier covers the everyday case of combining a handful of files; Pro adds larger files and bigger batches for heavy report consolidation.
Can I remove duplicates after stacking? +
Yes — appending often creates duplicate rows where files overlap. You can dedupe the combined result in the same flow by the columns you choose.
Do my files get uploaded to a server? +
No. Appending runs entirely in your browser, so your file contents never leave your device — verifiable in DevTools (no upload appears).