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Mortgage Overpayment Calculator

​Our mortgage overpayment calculator illustrates how much making an extra mortgage payment (or increasing your repayments) can save in interest costs.
Updated 8 December 2024
Our calculator helps answer:
  • How much interest can you save by making a lump sum mortgage payment?
  • How quick can you repay your mortgage by increasing the monthly repayment?
  • Whether you are on track to repay your mortgage before retirement?

Your Mortgage Overpayment Calculator is Brought to You by LifeDirect Mortgages

LifeDirect Mortgages, a trusted name in mortgage brokering across New Zealand, proudly supports this guide. We value LifeDirect Mortgages' commitment to helping New Zealanders secure the best home loan solutions, offering personalised advice tailored to your needs.

Whether you're a first-home buyer, looking to refinance, or exploring investment property options, LifeDirect Mortgages' experienced team makes the process simple, transparent, and stress-free. We proudly name them winners of our 2024 Editor's Choice for our favourite nationwide mortgage adviser.

We encourage you to contact their friendly experts to discuss your mortgage needs - you can learn more about LifeDirect Mortgages with our detailed review or visit their website.
mortgage overpayment calculator
Mortgage details
Current mortgage balance
This is the balance left to pay on your mortgage; you can find this on your annual mortgage statement
Remaining term
The length of time you have left to pay your mortgage, you can find this on your annual mortgage statement
Current interest rate
Your current mortgage interest rate, you can find this on your annual mortgage statement
Current monthly payment:
$0.0
Overpayment details
Regular monthly overpayment
Payments made each month that are extra to your monthly mortgage payments
- +
 
and/or
Lump sum overpayment
A one off payment made to your mortgage
- +
New monthly payment:
$0.0
Year Without overpayment With overpayment

Assumptions

​This calculator uses a number of assumptions:
  1. The model is based on a repayment mortgage - for an interest-only mortgage calculation, see our calculator. 
  2. There are no overpayment or early repayment fees - while floating mortgages don't charge this, fixed-rate deals do. Check with your lender before making any repayment.
  3. Repayments are the same every month over the entire life of the mortgage, and all years are of equal length.
  4. The interest costs are calculated daily and added monthly 
  5. The interest rate does not change over the life of the mortgage. 
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