What happens to a tab whose name has a slash in it?

The filename replaces it, because a slash separates directories on every system and a file cannot contain one in its name. The sheet name inside the resulting workbook is unaffected — only the name of the file on your disk is cleaned. The same applies to colons, which Windows refuses, and to a few other characters that would make a file awkward to open.

Can I split a very large workbook?

The work happens in your browser, so the limit is your machine's memory rather than an upload size — but every output file is held there at once until you download them, so a workbook with dozens of large tabs is the case to be careful with. If it stalls, split the source into two workbooks first and run each half.

Can I split by a column's values instead of by tab?

Not here — this splits on the structure the file already has, one output per sheet. Splitting by region or by month means grouping rows, which is a filter and a decision about which column defines a group; a spreadsheet's own filter or a pivot does it better and leaves you in control of the edge cases, such as the rows where that column is blank.

One File per Tab, and What a Split Leaves Behind

Published 9/16/2026 · 4 min read · File tools

Daniel Okonkwo — Front-end developer and tech writer at OneKitly

Web performance · File formats

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In short

Each sheet becomes its own workbook, written as an .xlsx named for the source file and the tab. What travels is the grid of values the sheet held; what does not is the formulas, the formatting and any reference that pointed at another tab — which is not a limitation so much as the reason the operation is useful. A budget workbook where the summary tab reaches into six departmental tabs cannot be split into six meaningful files while those references survive: each one would open with errors where its neighbours used to be. Sending values instead sends something that opens cleanly on any machine, and it sends only the tab that department is entitled to, which is usually the real motivation. If a formula's working matters to the recipient, list the formulas first and send that list beside the file — reading them is a separate operation and it leaves the workbook untouched.

Splitting a workbook writes one .xlsx per sheet, named after the tab. It carries the values across and not the formulas — which is the right default when the point is to send one department its own tab.

Sending one tab is a permissions decision

Hiding a sheet is not removing it. A hidden tab travels inside the file, opens with two clicks and shows up in full to anything that reads the workbook rather than displays it — which includes every converter on this site. The same goes for a filtered view, a white-on-white row and a column set to zero width: they are presentation, and presentation is not a boundary. If a recipient should not see the other departments' figures, the only reliable answer is to send them a file that does not contain those figures, and a split is the fastest way to produce one.

Split and merge are not quite inverses

Splitting a workbook and then appending the pieces gives you the sheets back, with their names and their values, and without the formulas and formatting that the first step already dropped. Merging rows and then splitting gives you one file, because a row merge produces a single sheet — the tabs are gone by then and nothing can bring them back. Neither is a fault; they are just operations on different things. The rule that follows is worth keeping: do the destructive step last, and keep the original until the result has been opened.

Split an Excel fileBreak a workbook into one .xlsx file per sheet, downloaded separately.Try the tool →

Frequently asked questions

What happens to a tab whose name has a slash in it?: The filename replaces it, because a slash separates directories on every system and a file cannot contain one in its name. The sheet name inside the resulting workbook is unaffected — only the name of the file on your disk is cleaned. The same applies to colons, which Windows refuses, and to a few other characters that would make a file awkward to open.
Can I split a very large workbook?: The work happens in your browser, so the limit is your machine's memory rather than an upload size — but every output file is held there at once until you download them, so a workbook with dozens of large tabs is the case to be careful with. If it stalls, split the source into two workbooks first and run each half.
Can I split by a column's values instead of by tab?: Not here — this splits on the structure the file already has, one output per sheet. Splitting by region or by month means grouping rows, which is a filter and a decision about which column defines a group; a spreadsheet's own filter or a pivot does it better and leaves you in control of the edge cases, such as the rows where that column is blank.

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Sources

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