The interest rate at which banks borrow funds from each other, in marketable size, in the London interbank market. This rate, a resetting rate or floating rate, is widely used by banks and financial institutions to price their products and calculate funding costs. Loans and debt instruments are usually traded using London interbank offered rate (LIBOR) as benchmark for calculation of interest payments.

Some interest rate futures contracts such as Eurodollar futures are cash settled based on LIBOR. LIBOR is also used for swaps (interest rate swaps) on the floating leg.

The British Bankers Association publishes LIBOR rates on a daily basis.