If your upload fails, it's probably due to one of the following reasons: The file size limit to upload a file and convert it for free is set to 100 Megabytes. In order to be able to upload bigger files, please take a look at our Premium services. The connection between your computer and our servers is temporarily unstable. Please try again later or from a different network or computer. The upload of large files is blocked by a proxy of your organization/provider. Sometimes, only the upload progress bar gets stuck, but the file has been fully uploaded and converted. You can check this when you register for free and look at the conversion history on your user dashboard. Uploading files is quite a bit slower than downloading files because most high-speed internet connections are designed to provide much better speed for downloading than uploading.