.OTS file extension

To open .OTS files on Windows, install an ODF-compatible spreadsheet app (for example, LibreOffice Calc).

To open a .OTS file, use an OpenDocument-compatible spreadsheet application (most commonly LibreOffice Calc). Don’t rename the extension—open it from within the spreadsheet app or use “Open with” to pick a compatible program.

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Last updated: June 11, 2026 · Reviewed by Julian Stricker

What “reviewed” means on this page

Format fit: whether the “what is this file?” description matches common real-world use of the extension, including category, typical MIME types, and aliases.
Opening paths: whether Windows / macOS / Linux steps read plausibly for current OS dialogs and default apps; we remove fantasy menus and unsafe shortcuts.
Security framing: whether risk notes match the extension class (for example executables vs plain data) and whether affiliate wording does not contradict the security section.
Sources and further reading: whether external links point to vendors, standards bodies, or other primary references where possible; we avoid inventing details we cannot ground.
Limits: this is clarity and safety-messaging QA, not a guarantee that every statement is exhaustive or that every binary you download is harmless.

Full methodology in the Imprint — The Imprint also states where AI is used and what that does—and does not—replace.

Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .OTS files

Use these platform-specific instructions to open .OTS files safely.

Windows

Install an ODF-compatible spreadsheet app (for example, LibreOffice Calc).
Right-click the .OTS file → Open with → choose your spreadsheet app (or open the app first and use File → Open).
If you want a new spreadsheet based on the template, use the app’s template workflow (open the template, then save the new document as .ODS).

Full Windows guide

Mac

Install an ODF-compatible spreadsheet app (for example, LibreOffice Calc).
Control-click the .OTS file → Open With → select the spreadsheet app.
Open the template and save the resulting spreadsheet as a normal document (commonly .ODS) if you need to edit data without overwriting the template.

Full Mac guide

Linux

Open the .OTS file in an ODF-compatible spreadsheet app (commonly LibreOffice Calc, often available via your distribution).
From your file manager: right-click → Open With → select the spreadsheet app (or open via File → Open in the app).
If the file should become a working spreadsheet, save a copy as .ODS to avoid modifying the original template.

Full Linux guide

iOS

iOS may not reliably open .OTS templates directly in the system preview; if it won’t open, transfer the file to a desktop app that supports ODF templates (for example, LibreOffice Calc) and open it there.

Full iOS guide

Android

Android support varies by app; if the file won’t open in your current office viewer, transfer it to a desktop ODF-compatible spreadsheet app (for example, LibreOffice Calc) to open and convert it to a regular spreadsheet (such as .ODS).

Full Android guide

Security notes

.OTS files are documents (not executables), but they can still be used to deliver unexpected content; only open templates from sources you trust.
If a template prompts you to enable special features (for example, automation features supported by your office suite), only allow them if you trust the template’s origin and purpose.
Because .OTS is a structured document format, a maliciously crafted file could potentially exploit parsing bugs in document software; keep your office suite updated before opening files from untrusted sources.

If you did not expect this file

This extension is usually plain data, text, or structured content—not a program by itself. The practical risk is social engineering (a scam attachment or misleading filename). For trusted senders you rarely need heavy-handed antivirus wording; use these tools when you want an extra check on unexpected downloads.

Avast

Avast offers free and premium antivirus software that protects against viruses, malware, ransomware, and phishing. Scan files before opening them to ensure safety.

Norton

Norton 360 delivers comprehensive antivirus protection, VPN, and identity theft monitoring. Scan files for threats before opening to keep your device secure.

We may earn a commission when you use affiliate links. This supports our free file extension guides.

Can't open this file?

These are the most common causes and fixes when .OTS files fail to open.

Common reasons

The .OTS file won’t open or shows an unknown format error
It opens, but I can’t edit (or edits don’t behave as expected)
The file looks corrupted or content is missing

Fix steps

Open the file from inside an ODF-compatible spreadsheet app (for example, LibreOffice Calc) using File → Open.
On desktop systems, use “Open with” and choose the spreadsheet app explicitly, then set it as the default for .ots if desired.

OS-specific troubleshooting

What is a .OTS file?

.OTS is the OpenDocument Format (ODF) spreadsheet template format. It uses the official media type application/vnd.oasis.opendocument.spreadsheet-template and is meant to be a reusable template for creating new spreadsheets, rather than a one-off spreadsheet document.

Background

An .OTS file is part of the OpenDocument family of formats standardized by OASIS. It represents a spreadsheet template: a file designed to be used repeatedly to generate new spreadsheets with consistent formatting, predefined tables, and other document settings.

In practice, organizations use .OTS templates to standardize things like invoices, timesheets, budgets, or reporting sheets so each new spreadsheet starts from the same structure. Compared with a regular ODF spreadsheet (.ODS), an .OTS file is intended to be used as a “starting point” rather than the final working document.

Because .OTS is an ODF-based format with a registered MIME type, it is broadly supported by ODF-capable office suites. LibreOffice Calc explicitly supports opening/saving OpenDocument spreadsheet templates (.ots).

Common MIME types: application/vnd.oasis.opendocument.spreadsheet-template

Common .OTS issues

The .OTS file won’t open or shows an unknown format error

This usually happens when your spreadsheet app doesn’t support OpenDocument templates or the file association points to the wrong program.

Open the file from inside an ODF-compatible spreadsheet app (for example, LibreOffice Calc) using File → Open.
On desktop systems, use “Open with” and choose the spreadsheet app explicitly, then set it as the default for .ots if desired.

It opens, but I can’t edit (or edits don’t behave as expected)

Some workflows treat templates as a starting point and expect you to create a new document from them. Editing the template directly can be confusing or may overwrite the template you intended to reuse.

Create a new document from the template (or open it and immediately “Save As” a working spreadsheet, commonly .ODS).
Keep the original .OTS unchanged and store it separately as your master template.

The file looks corrupted or content is missing

The download/copy may be incomplete, or the file may have been produced by software that wrote a non-compliant template.

Re-download or re-copy the file and try opening again in an ODF-compatible app (for example, LibreOffice Calc).
If it still fails, ask the sender to re-export/recreate the template as a standard ODF spreadsheet template (.OTS).

FAQ

What is an .OTS file used for?

It’s an OpenDocument Spreadsheet Template used as a reusable starting point for new spreadsheets—layout, styles, and predefined structure are saved so you can create consistent documents.

What program opens .OTS files?

An OpenDocument-compatible spreadsheet program. LibreOffice Calc supports opening and saving .OTS (OpenDocument spreadsheet templates).

Is .OTS the same as .ODS?

No. .OTS is a template meant to generate new spreadsheets, while .ODS is a regular spreadsheet document used for day-to-day data editing and saving.

Can I convert .OTS by renaming it to .ODS?

No. Renaming only changes the extension. Open the .OTS in a compatible spreadsheet app and use Save As/Export to create an .ODS document based on the template.

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