Most large supermarkets have coin sorting and weighing machines.However they do charge you approx 5% for the service,the charge goes to charity I think?
If you take a lot of change into a bank unsorted, they will give you a bunch of little money bags and tell you to sort it all. Then they'll weigh it when you take it back.
I've also discovered recently that some banks will not accept more than 5 change bags in one day. I assume for money laundering purposes.