How to Calculate Interest per Month on Credit Card

What is credit card interest?

Credit card interest is the cost of borrowing money through your credit card. It's calculated based on your outstanding balance and the interest rate (APR) charged by your card issuer. The interest is typically compounded daily, meaning you'll earn interest on both your original balance and any previously accrued interest.

Most credit cards charge interest on purchases and cash advances separately. Purchases are typically charged interest from the date of purchase, while cash advances are charged interest from the date of withdrawal. The interest is added to your statement balance each billing cycle.

APR vs. APY

When dealing with credit card interest, you'll often encounter two terms: APR (Annual Percentage Rate) and APY (Annual Percentage Yield). While they sound similar, they represent different calculations:

• APR is the simple interest rate charged by your credit card. It represents the annual cost of borrowing based on your average daily balance.
• APY is the effective annual interest rate, taking into account compounding. It gives you a more accurate picture of the true cost of borrowing.

The relationship between APR and APY is important because it shows how much more you'll pay if interest is compounded. For example, if your APR is 18%, your APY might be closer to 20% if interest is compounded daily.

How to calculate monthly interest

Calculating monthly interest on your credit card involves several steps. Here's a step-by-step method:

1. Determine your average daily balance for the billing period. This is typically calculated by adding your daily balances and dividing by the number of days in the billing cycle.
2. Multiply your average daily balance by your card's APR to get the annual interest charge.
3. Divide the annual interest charge by 12 to get the monthly interest charge.
4. Add the monthly interest to your previous balance to get your new statement balance.

This calculation assumes simple interest. For more accurate results, especially for longer periods, you should use the compound interest formula.

Example calculation

Let's walk through an example to illustrate how to calculate monthly interest on a credit card.

Scenario

• Average daily balance: $1,500
• APR: 18% (0.18 in decimal)

Step-by-step calculation

1. Calculate annual interest: $1,500 × 0.18 = $270
2. Calculate monthly interest: $270 ÷ 12 = $22.50
3. Add to previous balance: If your previous balance was $1,500, your new balance would be $1,522.50

This example shows how quickly interest can accumulate. Over time, even a small balance can grow significantly due to interest charges.

How to manage credit card interest

While it's important to understand how to calculate monthly interest, the best way to avoid paying excessive interest is through proactive management:

• Pay your balance in full each month - This is the simplest way to avoid interest charges entirely.
• Use the lowest interest rate card - If you must carry a balance, choose the card with the lowest APR.
• Transfer balances to a 0% APR card - Some cards offer 0% APR for a limited period, which can help you pay down debt without interest.
• Negotiate with your card issuer - If you're having financial trouble, contact your issuer to discuss possible solutions.
• Consider balance transfer cards - These cards often have lower APRs than regular credit cards, making them ideal for debt consolidation.