G-Eazy is about 6' 4
Although there isn't any official info on how tall G-Eazy is, you can easily find out how much one of his homies Drake is (just over 6ft).
I then looked up a photo of Drake and G-Eazy standing next to each other, and I'd say there's around 4 inches difference between them.
If you want to reach out to G-Eazy to ask him yourself, then why not try tweeting him? His Twitter profile is: https://twitter.com/g_eazy
