Frequently Asked Questions

Why choose

Here are top differences between and some similar websites:

  1. Some popular conversions use our exclusive conversion engines that you can't find elsewhere. For example: "Word to PDF" and "PDF to Word" conversions in the "PDF" category.
  2. provides some exclusive online services such as using intermediate formats for unsupported conversions or identifying file format by analyzing file binary signatures.
  3. supports batch conversion mode. You can convert a bunch of files with only a few clicks, just like using a desktop converter software on Windows.
  4. will automatically re-submit your form to another platform/server when conversion is failed on one platform/server. This significantly increases conversion success rate.
  5. is 100% free to use while some other websites may require your email address or restrict your file size to a low value unless you pay for "PRO" service.


Is it safe to convert files on

Yes, it's safe to convert files on All your files are treated as strictly confidential.

We have enabled HTTPS (Hypertext Transfer Protocol Secure) on all our servers. All file transmissions are through HTTPS instead of HTTP. HTTPS is an internet communication protocol that protects the integrity and confidentiality of data between your web browser and the site.

Your file's filename will be renamed to random 10 characters so only you can find it. Your files are only temporarily stored on our servers for 1-2 hours, after that they will be automatically deleted by a scheduled program.


What's the maximum file size and maximum execution time does support?

Different categories support different maximum file size and maximum execution time.

Category Max_file_size Max_URL_size Max_execution_time Multitask Exception
Document 40M 40M 5 minutes Queue Unknown format: 1M.
Ebook 40M 40M 6 minutes Queue CHM: 2M.
Image 200M 40M 3 minutes Asynchronous DWG: 10M.
Video 200M 40M 10 minutes Asynchronous Video merger: 1G.
Audio 200M 40M 10 minutes Asynchronous No exception.
Archive 40M 40M 5 minutes Asynchronous No exception.


Why is my online file conversion failed?

Here are the top 5 reasons that may cause online file conversion failure:

  1. The server may be down or busy at the moment. It doesn't have enough CPU or memory resource to complete conversion. Tips: our servers are idle on weekends and holidays.
  2. The source format is not supported. For example, many users tried to convert WLMP file which is a movie project file that doesn't support.
  3. The source file may be corrupt, DRM protected or have wrong file extension name.
  4. The source file may be too big or too complicated to be converted in time. We restrict some conversions in 180 seconds. The conversion will be terminated when time is up.
  5. Document and ebook files can't be converted asynchronously. It may return overtime error if the conversion queue is too long.


How can I run a conversion that doesn't support, for example: XLS to DOC?

Some unpopular conversions that are not listed on are actually supported. For example: converting audio file or image file to video file. You can directly run these conversions without problem.

Some conversions that doesn't support can use intermediate file to do. Use XLS to DOC as example: You can convert XLS file to PDF or XPS as intermediate file first, then convert the PDF or XPS file to DOC file. Using intermediate file may not have great results as direct conversion but can get the job done.

You can search a conversion at format search page. Just select a source file format, a target file format, and click "Search" button to start searching. It will list all possible conversions that use intermediate file.


It supports DOCX to PDF conversion in "PDF", "Document" and "Ebook" category. Which category should I choose?

DOCX to PDF conversion in "PDF" category uses our exclusive algorithm while conversions in the other categories use universal algorithm.

The conversion in "Ebook" category is designed as a pipeline. The input format is first converted to XHTML by the appropriate input plugin. This XHTML is then transformed. In the last step, the processed XHTML is converted to the specified output format by the appropriate output plugin. Using pipeline is necessary to support vast formats with minimal source codes, however the results of the conversion can vary greatly. Some formats convert much better than others.

Compare conversion in "Ebook" category, conversion in "PDF" category is designed as direct transaction. All source DOCX file elements such as text, image, table, bookmark will be directly converted to target PDF file elements on the fly without any middle file created. It works fast and may have better results.


Can I directly use the converted file online without downloading it, for example: set password to a PDF file just converted?

Yes, you can reuse the file just converted. Here are steps to set password to a PDF file just converted.

1) Right click on the output PDF file, and click "Copy link address" to copy the file link address to clipboard. The link address is directly linked to actual online file without rewriting.
2) On the "Lock PDF" page, click on "URL" button to switch source file from local file to online file.
3) Press "Ctrl+V" to paste the file link address copied in step 1 in input box, set password and click submit button. The processing will be very quick since no file downloading or uploading.


The file conversion progress starts at 0% again when it reached 100%. Why?

The file conversion will automatically retry another platform/server when it's failed, so you don't need to click the submit button again.

The top reason that causes online conversion failure is the server is down or busy. Therefore will automatically re-submit your form to another platform/server when conversion is failed. For example: It will try converting your file on Windows server NO.4 if it fails to convert your file on Linux server No.3.

We have deployed multiple Windows and Linux servers to increase conversion success rate. Please be patient while converting.


Why does support so many file formats?

One of the best things about online conversions is that we can install as many programs, codecs, fonts, plugins and extensions as possible.

Since we started to develop shareware at year 2000, we tried hard to reduce shareware setup file size. Smaller setup file size can reduce bandwidth usage and make downloading faster. However we don't have file size problem anymore on online programs. We can't fill 1TB server storage up no matter how many program we try to install. We have installed a third-party program which file size is more than 100mb just to support one SID format.

Some file formats can only be opened on Linux platform and some file formats can only be opened on Windows platform. Therefore we deployed both Linux and Windows servers for this situation. supports 243 file formats by far and will continue to support more.