Re: how to increase upload size of a documnet upto 20 MB….in an asp.net application. Aug 04, 2013 08:25 AM|LINK You likely will need to update your maxRequestLength within your web.config to handle files and uploads that are large (as the default limit is often 4MB). This can be handled within the section of your web.config or the section if you want to handle it at the IIS level (both are probably a good idea). It’s important to know that maxAllowedContentLength is measured in bytes and maximumRequestLength is measured in kilobytes when settings these values so you’ll need to adjust them accordingly if you plan on handling much larger files : If you wanted to use 20MB as a limit, you would need to change the values to the following respectively : If you don’t see these sections within your existing web.config file, you’ll simply need to copy them in. Updating the maxRequestLength property is likely going to be the easiest method of handling this, however there are alternatives such as libraries like NeatUpload, which are designed to handle large files and can handle uploading files as streams to your preferred method of storage.