Why does blockchain.info show a different balance from bitcoin-qt? I just created a wallet on blockchain.info by importing my wallet.dat from Bitcoin-QT. My Bitcoin-QT shows a balance of 3.991 BTC, while blockchain.info shows a balance of 3.016.

Where does the difference come from, and which one is 'correct'?
Either one of the factors may affect either balance:


There is a double spend against one of your accounts
Some transaction might not have yet been included in a block and one program does not see it yet
There can be an error in one of the programs that skipped over some transactions. In case of the client, you should try rescanning the blockchain to make sure all data is properly extracted in case you suspect an error


You should make sure your client is fully synchronised and all your transactions have at least one confirmation.

You should generally trust the place where you issue your transactions from to have an accurate balance of your outgoing transactions, and blockchain.info for the information available everywhere else.