Term
Effective annual rate (EAR)
A BudgetBurrow glossary entry. Scroll down for a plain-English definition and related concepts.
A BudgetBurrow glossary entry. Scroll down for a plain-English definition and related concepts.
The effective annual rate (EAR) represents the true annual rate of interest earned or paid on a financial product after accounting for the effects of compounding over a year. EAR reflects the impact of the frequency with which interest is applied, distinguishing it from nominal or stated rates that ignore compounding.
EAR developed as a standardized measure to compare interest rates on financial products that compound at different intervals, addressing confusion caused by nominal rates that do not reflect compounding frequency. It allows transparent and consistent evaluation across loans, deposits, and investments irrespective of the compounding schedule.
EAR is calculated by converting the nominal (stated) annual rate into a rate that accounts for the number of compounding periods per year. For a given nominal rate, interest is compounded periodically (monthly, quarterly, etc.), so the EAR formula adjusts for how often that compounding occurs. In practice, once the compounding frequency and nominal rate are known, EAR quantifies the actual percentage paid or earned over the course of a year.
There are no formal types of EAR, but its calculation varies across contexts depending on compounding intervals (daily, monthly, quarterly, etc.). In some markets, EAR may be referenced as annual percentage yield (APY) for deposits, while for loans, it may informally be compared to annual percentage rate (APR), though APR may exclude compounding effects and fees.
EAR is used when comparing savings accounts, term deposits, loans, or other interest-bearing products with different compounding schedules. It is particularly relevant for budgeting, evaluating funding options, or analyzing projected investment returns, especially when interest is not compounded annually.
A savings account offers a nominal interest rate of 5% compounded monthly. The EAR is calculated as follows:
EAR = (1 + 0.05/12)12 − 1 ≈ 5.12%.
Although the nominal rate is 5%, the impact of monthly compounding raises the actual annual return to 5.12%.
EAR reveals the true cost of borrowing or real return on investments, enabling accurate product comparison and financial planning. Ignoring EAR can result in underestimated costs for loans or overstated returns for savings, potentially leading to suboptimal financial decisions.
When compounding frequency increases—such as daily versus monthly—the EAR rises disproportionately relative to the nominal rate. However, as compounding becomes extremely frequent, the additional increase in EAR diminishes, approaching a theoretical maximum known as continuous compounding.