A bank advertises an APR of 5.5% on personal loans. How much more is the APY when the rate is compounded monthly as compared to when it's compounded quarterly? Explain your answer.

use this to answer the question:
Using the Convert APR to APY calculator:
APR as a decimal (a) =
n = 12 (compounded monthly = 12 times per year)
APY = %
APR as a decimal (a) =
n = 4 (compounded quarterly = 4 times per year)
APY = %
Find the difference: % - % = %

1 answer

To determine how much more the Annual Percentage Yield (APY) is when the APR of 5.5% is compounded monthly compared to being compounded quarterly, we first need to convert the APR to APY using the formula for APY:

\[ APY = \left(1 + \frac{a}{n}\right)^n - 1 \]

where:

  • \( a \) is the APR expressed as a decimal (0.055 for 5.5%)
  • \( n \) is the number of compounding periods per year.

Step 1: Calculate APY for Monthly Compounding

  1. Convert APR to Decimal: \[ a = 5.5% = 0.055 \]
  2. Set n for Monthly Compounding: \[ n = 12 \]
  3. Calculate APY: \[ APY_{monthly} = \left(1 + \frac{0.055}{12}\right)^{12} - 1 \] \[ APY_{monthly} = \left(1 + 0.0045833\right)^{12} - 1 \] \[ APY_{monthly} = (1.0045833)^{12} - 1 \approx 0.056875 \] \[ APY_{monthly} \approx 0.056875 \times 100 \approx 5.69% \]

Step 2: Calculate APY for Quarterly Compounding

  1. Set n for Quarterly Compounding: \[ n = 4 \]
  2. Calculate APY: \[ APY_{quarterly} = \left(1 + \frac{0.055}{4}\right)^{4} - 1 \] \[ APY_{quarterly} = \left(1 + 0.01375\right)^{4} - 1 \] \[ APY_{quarterly} = (1.01375)^{4} - 1 \approx 0.056370 \] \[ APY_{quarterly} \approx 0.056370 \times 100 \approx 5.64% \]

Step 3: Find the Difference

Now we subtract the APY for quarterly compounding from the APY for monthly compounding:

\[ \text{Difference} = APY_{monthly} - APY_{quarterly} \] \[ \text{Difference} = 5.69% - 5.64% \approx 0.05% \]

Final Answer:

The APY is approximately 0.05% higher when the APR is compounded monthly as compared to being compounded quarterly.