Interest Rate

The percentage of a loan that is charged as interest to the borrower. Can be quoted as a base rate plus a spread with the base rate being measured based on common rates such as the LIBOR, Fed rate, and prime rate.

All-In Rate

The complete rate that the borrower pays. Calculated as Base + Spread.

Base

Interest rates a central bank will charge to commercial banks for a loan.

Spread

Difference between the rate the bank is charged (Base Rate) and what they are charging a borrower (All-In Rate).