Credit Card Payoff Calculator
See how long it takes to pay off your credit card and the total interest you will pay. Compare minimum payments versus fixed extra payments.
About this calculator
This calculator implements credit card minimum payment rules from NZ Consumer Protection. Last consulted 20 March 2026. Verify the figures yourself by following the link.
Current NZ credit card rates
FY 2026-27 (typical big-4 banks)- •Standard purchase rate: 18–22% p.a.
- •Cash advance rate: 22–25% p.a.
- •Low-rate cards: 12–13% p.a.
- •Minimum repayment: 2% of balance or $25 (greater)
- •Annual fee: $0–$500
- •Interest-free days: Up to 55 (if paid in full)
Disclaimer
This calculator provides estimates for general information purposes only. Results should not be relied upon as professional financial, tax, or legal advice. Tax rates and thresholds are based on publicly available IRD data and may change. Always consult a qualified tax agent or financial adviser for advice specific to your circumstances.
How credit card payoff time is calculated
Credit cards compound monthly at brutal rates (typically 18-22% pa in NZ). Paying only minimums can take 20+ years and cost 3× the balance in interest.
- 1
Calculate monthly interest
Monthly_interest = balance × (annual_rate ÷ 12)
$5,000 @ 21% = $87.50 interest per month.
- 2
Minimum payment trap
Min_payment = max($25, balance × 2%)
Paying only 2% means most goes to interest — balance barely drops.
- 3
Payoff time calculation
Months = log(payment ÷ (payment − bal × i)) ÷ log(1 + i)
Pay more than minimum to escape interest spiral.
Worked example
Inputs: $5,000 balance, 21% APR, paying $200/mo vs minimum
Result: $200/mo = 30 months, $1,038 interest. Minimum-only = 25+ years, $11,000+ interest!
Frequently Asked Questions
What interest rates do NZ credit cards charge?
What is the minimum payment trap?
Which debt repayment strategy is best — avalanche or snowball?
How do balance transfers work in NZ?
Shows how long it takes to pay off NZ credit card debt and total interest paid, given your balance, interest rate, and monthly payment. Makes the case for paying more than the minimum.
How this calculator works
Each month, interest accrues on the remaining balance (balance × monthly rate), then the payment is applied. Months to payoff = −log(1 − (balance × monthly rate) / payment) / log(1 + monthly rate). Minimum repayment is typically 2% of balance or $20, whichever is greater.
NZ Credit Card Key Facts
| Typical NZ credit card interest rate | 19.95%–22.95% p.a. |
| Minimum repayment (typical) | 2% of balance or $20 (whichever is greater) |
| NZ average credit card debt | ~$2,500 |
| Interest-free period | 44–55 days (purchases only, not cash advances) |
| Cash advance rate | Often higher than purchase rate; no interest-free period |
Interest-free period only applies when you pay your full balance each statement. Partial payments void the interest-free period.
Worked Examples
$5,000 balance at 20% p.a., paying only the minimum (2% or $20)
Takes approximately 32 years to repay, with around $8,000 in total interest paid.
- Starting balance: $5,000
- Monthly rate: 20% / 12 = 1.667%
- Month 1 minimum: $5,000 × 2% = $100
- Month 1 interest: $5,000 × 1.667% = $83.33
- Month 1 principal reduction: $100 - $83.33 = $16.67
- As balance falls, minimum payment falls — extremely slow payoff
- Total interest over ~32 years: ~$8,000
- Paying minimums is one of the most expensive ways to carry debt
$5,000 balance at 20% p.a., paying a fixed $200/month
Paid off in approximately 29 months, total interest ~$800.
- Balance: $5,000, rate 20% p.a. (1.667%/month), payment $200/month
- Months = -log(1 - ($5,000 × 0.01667) / $200) / log(1.01667)
- Months = -log(1 - 0.4167) / log(1.01667)
- Months = -log(0.5833) / 0.007252
- Months = 0.5397 / 0.007252 ≈ 29 months
- Total repaid: $200 × 29 = $5,800 (approximately)
- Total interest: $5,800 - $5,000 = $800
- Saving vs minimum payments: ~$7,200 in interest
Built and maintained by Konstantin Iakovlev. Data sourced from the IRD and official New Zealand government sources.
Last reviewed: