OST to HTML

Convert OST to HTML turns every email stored in an Outlook .ost file into its own HTML document, placing the message headers in a top‑of‑document metadata block and embedding any inline images directly in the file. The converter processes the entire archive in one submission and returns a single ZIP that contains one HTML file per message. It handles any number of messages that fit within the service’s file‑size limits; converting other Outlook formats such as .pst is outside the tool’s scope.

Message headers become a clear top‑of‑document block

For each email, the converter extracts the From, To, Cc, Subject and Date fields and formats them as a metadata block that appears at the very beginning of the HTML file, preserving the original ordering and values exactly as they were stored in the OST.

Inline images are embedded directly in the HTML

Any picture that was embedded in the original email body is converted into a base‑64 data URI and placed in the HTML where the image originally appeared, so the visual layout is retained without needing external files.

Message body stays selectable and searchable

The HTML output contains the complete rich‑text body of the message, including formatting such as bold, italics, lists and tables, which remains fully selectable and searchable in a web browser.

Limits and scope

File size per submission

Free tier handles smaller OST files; a free Aspose account raises the per‑file size limit, and paid tiers increase it further.

Retention period

Uploaded OST files and generated ZIP archives are stored for 24 hours after conversion completes.