Two jobs, one page: split a big spreadsheet into many small ones, or merge Excel files into one workbook. Splitting works by the value of a column you choose — one file per city, region, salesperson or month — or every N rows, and the header row is copied into every single part. Merging accepts CSV and XLSX together, matches the columns by name and can stamp each row with the file it came from. Free, no sign-up, no watermark, no daily quota: everything runs inside your browser, so your files never leave your device.
Pick a tab: Split for one file into many, Merge to combine CSV files into one.
Splitting: choose the column to split on, or the number of rows per file. Merging: check the automatic column matching and fix anything that should line up differently.
Look at the preview — file names, row counts, the merged table — then download the ZIP or the single merged CSV/XLSX.
Search for this problem and you get a VBA macro to paste into the developer console, a PowerShell one-liner, or a pandas groupby loop. They all work — and they all mean debugging someone else's code on a file that matters. This page does the same three things those scripts do: group the rows by a column, copy the header into each group, and name the files safely. You see the list of parts before you download, so nothing happens silently.
Why not the usual online converters? Because free server-side tools ration the work. The GroupDocs free merger allows 5 merges per day and at most 10 files per merge. Aspose's online splitter uploads your workbook, can only split it along its sheet tabs — not by the values inside a column — and states that your file stays on its servers for 24 hours. Here there is no quota, no file-count cap and no upload at all: the split and the merge happen on your own computer, which is also why they are instant.
Open the Split tab, load your XLSX or CSV file, tick that the first row is a header, choose the column you want to split on — for example City, Region or Salesperson — and every unique value in that column becomes its own file. The header row is copied into each part, and all parts download together in one ZIP.
No. Free online mergers usually cap you: the GroupDocs free merger allows 5 merges per day and at most 10 files at a time. Here the work happens on your own computer, so there is no daily quota and no file-count limit — the only real limit is your machine's memory.
No. Everything runs in your browser with JavaScript, so the file never leaves your device. Server-based tools work differently — Aspose's online splitter, for example, uploads your workbook and keeps it on its servers for 24 hours, and it can only split a workbook along its sheet tabs, not by the values inside a column.
No code at all. The usual answers to this problem are a VBA macro, a PowerShell script or a pandas groupby loop in Python. This tool does the same grouping, header copying and file naming with two clicks, and you can see the resulting file list before you download anything.
CSV files above 20 MB are split in streaming mode, so the file is read in chunks instead of being loaded whole — that keeps memory low, but streaming output is CSV only. XLSX files are always fully expanded in memory: roughly 200,000 rows can use 200-300 MB of RAM, so the tool warns above 50 MB and warns strongly above 200 MB. On iPhone and iPad the limits are lower because Safari caps memory per tab.