Credit Card Interest Calculator
Updated 3 May 2026
Our credit card calculator works out how long it will take you will take to pay off your current credit card balance, and the total interest you'll pay. Just enter your balance, interest rate and how much you usually pay off each month and let us do the work.
Know This: If you want to reduce your interest costs, ask your bank to lower your credit card limit. The less you owe, the less interest you'll pay and the sooner you can pay it off.
Our credit card calculator works out how long it will take you will take to pay off your current credit card balance, and the total interest you'll pay. Just enter your balance, interest rate and how much you usually pay off each month and let us do the work.
Know This: If you want to reduce your interest costs, ask your bank to lower your credit card limit. The less you owe, the less interest you'll pay and the sooner you can pay it off.
Balance Transfer Credit Card Calculator
See how much you would save by moving your credit card debt to a balance transfer card with a 0% promotional period.
Current card
Time to pay off
2 years 10 months
Total interest
$1,615
Total cost
$6,615
vs
Balance transfer card
Time to pay off
2 years 6 months
Interest + fees
$902
Total cost
$5,902
A balance transfer would save you $713
By switching to a 0% balance transfer card, you would clear the debt 4 months faster and save around $713 in interest over the life of the debt. Compare current NZ balance transfer offers.
Time saved
4 months
Total savings
$713
After transfer fee
Balance after promo ends
$3,800
After 12 months at 0%
Important balance transfer rules: You cannot transfer between cards from the same bank. Don't make new purchases on the new card during the promo (they often attract the standard rate). After the promotional period ends, any remaining balance reverts to the standard rate (often 18-22.95%). For the best result, work out your monthly payment as balance ÷ promo months to clear it before the promo ends.
MoneyHub Founder Christopher Walsh explains how to use our credit card interest calculator in the video below:
Get rid of credit card debt FAST
If you have a large balance (i.e. over $5,000) and it is going to take more than 3 months to pay off your credit card, there is hope. A balance transfer credit card could save you hundreds of dollars in interest costs. It can also give you some breathing space, interest-free monthly payments to let you pay off your credit card on your terms.
Credit Card Interest Frequently Asked Questions
We have listed a number of credit card interest and payment FAQs to help you navigate to a lower credit card balance.
Why am I being charged interest on my credit card?
Interest is charged when you don't fully pay off your credit card balance on the due date. For example, if your statement says $4,000 is due on 15 March and you only pay $500, you will pay interest on the $3,500 that is unpaid. You will be charged interest until the balance is fully repaid.
Interest is charged when you don't fully pay off your credit card balance on the due date. For example, if your statement says $4,000 is due on 15 March and you only pay $500, you will pay interest on the $3,500 that is unpaid. You will be charged interest until the balance is fully repaid.
How is credit card interest calculated in New Zealand?
Interest is calculated daily and charged to a balance at the end of the month if you do not pay off the entire balance. For example, if you have a credit card with an interest rate of 24% p.a. and a $1,000 balance to pay that is overdue, you will pay 2% per month (calculated as 24% / 12 months) on the balance until it is repaid. This works out to $20 per month, or $240 a year. The higher the interest rate and the larger the balance owed, the more dollars you will spend on making interest payments.
Interest is calculated daily and charged to a balance at the end of the month if you do not pay off the entire balance. For example, if you have a credit card with an interest rate of 24% p.a. and a $1,000 balance to pay that is overdue, you will pay 2% per month (calculated as 24% / 12 months) on the balance until it is repaid. This works out to $20 per month, or $240 a year. The higher the interest rate and the larger the balance owed, the more dollars you will spend on making interest payments.
When should I pay my credit card bill to avoid interest?
As soon as possible is the best answer. If you have spare money and have a habit of spending more than you should, then it's a good idea to pay down a credit card balance as soon as you can.
As soon as possible is the best answer. If you have spare money and have a habit of spending more than you should, then it's a good idea to pay down a credit card balance as soon as you can.
Do you get charged interest if you pay minimum payment?
Yes - you will be charged interest on the balance that remains unpaid. For example, if your balance is $1,000 and the minimum payment is 5% and you make a $50 payment, you will pay interest on the $950 owing.
Yes - you will be charged interest on the balance that remains unpaid. For example, if your balance is $1,000 and the minimum payment is 5% and you make a $50 payment, you will pay interest on the $950 owing.
What is the average credit card interest rate?
Based on our review of the range of options in the market, but we believe 20% to 24% p.a. is an accurate figure.
Based on our review of the range of options in the market, but we believe 20% to 24% p.a. is an accurate figure.
Does getting charged credit card interest affect your credit score?
Yes, because not paying off a credit card balance in full is a negative credit history event. Our guide to credit scores has more information.
Yes, because not paying off a credit card balance in full is a negative credit history event. Our guide to credit scores has more information.
What is a good interest rate on a credit card?
A 'good' interest rate is 0%, which is available for up to 12 months with a balance transfer credit card. Otherwise, the lower the percentage, the better the credit card all other things being equal. A competitive interest interest rate is anything below 15% - our guide to low interest credit cards has more information.
A 'good' interest rate is 0%, which is available for up to 12 months with a balance transfer credit card. Otherwise, the lower the percentage, the better the credit card all other things being equal. A competitive interest interest rate is anything below 15% - our guide to low interest credit cards has more information.
How do I get my bank or credit card company to lower my interest rate?
The only way to reduce your credit card interest rate is to switch to a better credit card.
The only way to reduce your credit card interest rate is to switch to a better credit card.
