What is the size of android Marshmallow source code? I have downloaded 26.8 gb but the repo tool is still going on and I am on a very slow connection in India.I used the standard instruction provided on the website to download.
Generally, the size of source code varies depending on if it is compressed or raw..

The full source code ranges around 20GB's as of now (slightly varies with ROM) and be downloaded using the repo tool.. 

The compressed source code varies around 2GB..

Here's an XDA Thread which provides compressed source code files (and updated quite frequently):
[INDEX] [SOURCES] [DevXchange] Android Sources Highly Compressed &amp; Developer Exchange