<p>How to find out size of session in ASP.NET from web application?</p>

I think you can find that information by adding
Trace="true"
to the page directive of a aspx page. Then when the page loads you can see a large number of details regarding the page request, including session information i think.
You can also enable tracing in your entire application by adding a line to your web.config file. Something like:
```
```
<trace enabled="true" requestLimit="10" pageOutput="true" traceMode="SortByTime" 
 localOnly="true"/>
```
```