This New Zealand calculator compares directing spare money to extra KiwiSaver contributions against paying down your mortgage. It weighs the guaranteed return of mortgage interest saved against KiwiSaver growth and the employer and government contributions, while noting KiwiSaver is locked away, helping you choose where spare money does the most good.
Mortgage paydown earns a guaranteed return at your mortgage rate with no risk and frees cash sooner. KiwiSaver may add employer and government contributions and market growth but is locked until 65 or a first home. Estimate only, not financial advice.
The calculator grows your spare monthly amount at your mortgage rate, which represents the guaranteed value of paying down the loan, since each dollar saves interest at that rate. It separately grows the same amount at your KiwiSaver return, adding the yearly employer and government extras you enter. Comparing the two shows which builds more value, while the notes remind you the mortgage option is risk-free and accessible, and KiwiSaver is locked away.
Putting $400 a month toward a 6.5% mortgage builds value as if earning 6.5% guaranteed, around $116,000 over 15 years. The same into KiwiSaver at 6% plus $521 a year of extras could build a similar or larger sum, but it is locked until 65 or a first home, which is the key trade-off.
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