Yield curves plot the interest rates or yields of fixed-rate debt instruments, typically bonds, against their various maturities. This helps investors and economists understand the relationship between the interest rates and the time to maturity of debts. In finance, the yield curve is used to illustrate the term structure of interest rates and can indicate economic expectations, such as growth and inflation. The most common yield curve shapes are normal, inverted, and flat, each signifying different economic conditions.