If you put superdelegates aside, Hillary has 1243 pledged delegates and Bernie has 975. 2049 delegates are still up for grabs. If Bernie wins 56.54% of the remaining delegates, he will tie with Hillary. As far as the superdelegates are concerned, they are not bound. They can switch their allegiance to Bernie the same way they switched from Hillary to Obama in 2008. So, Bernie can still win the nomination. All he needs is 56.54% of the remaining delegates which doesn't sound very improbable.