What is the ruling on bank interest, and what is the difference between an Islamic bank and a non-Islamic bank in determining the value of interest, and do the loans of Islamic banks make their transactions permissible?

The ruling on banking transactions depends on whether the contract conforms to or violates the provisions of Islamic law (Sharia (definition)). Banks that enter into a Mudarabah (definition) (profit-sharing) contract with the capital owner, based on a known percentage of the profit, have valid and permissible dealings. However, banks that give the capital owner a percentage of the capital, not the profit, have a contract that is undoubtedly void. If a bank provides loans that are to be repaid with a stipulated increase, then it is dealing in explicit usury (riba), which is unanimously forbidden. But if "loans" refer to financing operations conducted by some banks through Murabahah (definition) (cost-plus financing) in accordance with Sharia guidelines, then these are permissible.