Report Size and Limits
The report server does not limit the size of a report definition. However, ASP.NET imposes a maximum size for items that are posted to the server. By default, this limit is 4 megabytes (MB), or 4,168 kilobytes (KB). If you upload or publish a report definition that exceeds this limit to a report server, you receive an HTTP exception. In this case, you can modify the default by increasing the value of the maxRequestLength element in the Machine.config file.
For the most part, report definitions rarely exceed 4 MB. A more typical size is less than 100 KB. However, if you include embedded images, the encoding of those images can result in large report definitions that cause an HTTP exception.
ASP.NET imposes this limit to reduce the threat of denial of service attacks against the server. Increasing the value of the upper limit undermines some of the protection that this limit provides. Increase the value only if you are confident that the benefit of doing so outweighs any additional security risk.
Determining the Size of a Report That Includes Data
Reporting Services does not measure the size of a report that includes data. To determine the size of a rendered report, you should export the report and save it to a file. The format you choose may affect the file size. Consider saving a report in multiple formats to compare the file size.
Note Report size can vary at run time, where changes in size are attributed to how much data is returned. For example, parameterized reports may be larger or smaller based on which parameter values you provide.