Convert OST to WebP
Convert OST to WebP online: cached Outlook messages laid out as readable pages, saved as a compact WebP image. Free, no sign-up.
Drop your OST files here
Up to 200MB per file.
Conversion Settings
Files are encrypted and auto-deleted after conversion
How to Convert
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Upload your OST files
Drag and drop or select OST files from your device. You can upload multiple files at once.
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Configure Output
Choose any available WebP output options, then start the conversion.
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Download WebP files
Once conversion finishes, download your files individually or as a compressed ZIP archive.
Why convert OST to WebP?
Outlook keeps an OST file as an offline copy of an Exchange, Microsoft 365 or Outlook.com mailbox on your computer. The image shows the body of each message from the offline mailbox, formatted text and tables included, stacked in turn beneath an “OST mailbox” heading.
WebP stores the rendered image in a modern, efficient format, so the file is noticeably smaller than an equivalent PNG or JPG.
Frequently Asked Questions
How do I convert OST to WebP?
Drop your OST file above and press Convert. Our servers read the offline data file, export its messages and render them one after another as pages. The result is saved as a compact WebP image, ready to download.
Can I turn an OST file into WebP without Outlook installed?
Yes. The OST file is read directly on our servers, so its cached messages are laid out and rendered without Outlook or a connection to the mail server.
Which parts of each OST message are rendered in the WebP?
Each message body is rendered with its text, formatting and tables, and the messages follow one another beneath an “OST mailbox” heading.
What happens when a OST file fills several WebP pages?
Each page is rendered at 144 dpi and saved as its own WebP image, named page-1, page-2 and so on, and they download together as one ZIP. A single page downloads as one WebP file.
How much smaller is the WebP from a OST file?
WebP typically produces files around a quarter to a third smaller than JPG at similar visual quality, and far smaller than PNG, while text and lines stay clear.
Is my .ost file kept private?
Your file is uploaded over an encrypted connection, converted on our servers and deleted automatically within 24 hours. We never read, share or keep your files, and no account is needed.