Interest Gaining Credit Card Calculator

Credit cards that earn interest on your balance can be a powerful tool for growing your money. This calculator helps you determine how much interest you'll earn on your credit card balance over time, taking into account the Annual Percentage Rate (APR) and the compounding frequency.

How the Interest Gaining Credit Card Calculator Works

Credit cards that earn interest typically offer a higher APR than regular checking or savings accounts. This interest is calculated on your outstanding balance and can be compounded daily, monthly, or annually, depending on the card's terms.

The calculator uses the compound interest formula to determine how much your balance will grow over time. The formula accounts for the APR, the compounding frequency, and the time period you specify.

Compound Interest Formula

A = P × (1 + r/n)^nt

Where:

A = the future value of the investment/loan, including interest
P = the principal investment amount (the initial deposit or loan amount)
r = the annual interest rate (decimal)
n = the number of times that interest is compounded per unit t
t = the time the money is invested or borrowed for, in years

For credit cards, the principal (P) is your outstanding balance, the annual interest rate (r) is the APR, and the compounding frequency (n) is typically daily, monthly, or annually.

How to Use the Calculator

Enter your current credit card balance in the "Current Balance" field.
Enter the Annual Percentage Rate (APR) offered by your credit card in the "APR" field.
Select the compounding frequency from the dropdown menu (daily, monthly, or annually).
Enter the number of years you want to calculate interest for in the "Time Period" field.
Click the "Calculate" button to see your results.

The calculator will display the total interest earned and the future value of your balance after the specified time period.

Formula Used

The calculator uses the compound interest formula to calculate the future value of your credit card balance. The formula is:

A = P × (1 + r/n)^nt

Where:

A = Future value of the balance
P = Current balance
r = Annual Percentage Rate (APR) as a decimal
n = Number of times interest is compounded per year
t = Time period in years

For the interest earned, the formula is:

Interest = A - P

The calculator also provides a chart showing the growth of your balance over time.

Worked Examples

Example 1: Daily Compounding

Suppose you have a credit card balance of $1,000 with an APR of 18% compounded daily. You want to know how much interest you'll earn in 1 year.

Using the formula:

A = 1000 × (1 + 0.18/365)^365×1

A ≈ $1,200.36

Interest = $1,200.36 - $1,000 = $200.36

Example 2: Monthly Compounding

With the same $1,000 balance and 18% APR, but compounded monthly over 1 year:

A = 1000 × (1 + 0.18/12)^12×1

A ≈ $1,196.57

Interest = $1,196.57 - $1,000 = $196.57

Notice that daily compounding yields more interest than monthly compounding for the same APR and time period.

Frequently Asked Questions

What is the difference between APR and APY?

APR stands for Annual Percentage Rate, which is the simple annual interest rate on a loan or credit card. APY stands for Annual Percentage Yield, which is the effective annual interest rate that takes into account compounding.

For example, a credit card with a 18% APR compounded daily would have an APY of approximately 18.6%.

How often is interest compounded on credit cards?

Interest on credit cards is typically compounded daily. However, some cards may compound monthly or annually, depending on the issuer's terms.

Can I use this calculator for personal loans?

This calculator is specifically designed for credit cards that earn interest. For personal loans, you should use a loan calculator that accounts for different repayment terms and interest calculation methods.

Is it better to have a higher APR or lower APR?

For credit cards that earn interest, a higher APR is generally better because it means you'll earn more interest on your balance. However, you should also consider other factors such as fees, rewards, and your ability to pay off the balance in full each month.