Mortgage repayments and lifetime totals
Calculate NZ mortgage repayments and what the loan costs over its term.
Uses the standard amortisation formula on a rate compounded monthly, which is how NZ lenders quote.
The fortnightly and weekly figures are the monthly repayment divided by the average number of fortnights (2.174) and weeks (4.348) in a month, matching calculate.co.nz. They are the same annual amount paid more often, NOT an accelerated schedule, so they do not shorten the term. Paying half the monthly amount every fortnight is the accelerated version, and it is a different calculation.
annual_interest_rate_pct is a percentage, so 5.99 rather than 0.0599.
Assumes one constant rate for the whole term. Real NZ mortgages are usually fixed in one to five year tranches and re-fixed at whatever the rate is then, so treat a 30 year total as an illustration of the shape rather than a forecast.
Request
- Base URL: https://api.calculate.co.nz
- URL: https://api.calculate.co.nz/v1/mortgage
- Auth: API key in header X-API-Key
Request body
Example request
{
"annual_interest_rate_pct": 5.99,
"loan_amount": 750000,
"term_years": 30
}Response
Repayments at three frequencies, plus total interest over the term.
Example response
{
"disclaimer": "Estimate only using a constant nominal rate compounded monthly. Actual repayments depend on your lender's terms, fees, and rate changes. Not financial advice.",
"result": {
"annual_interest_rate_pct": 5.99,
"fortnightly_repayment": 2066.15,
"interest_share_pct": 53.62,
"loan_amount": 750000,
"monthly_repayment": 4491.81,
"principal_share_pct": 46.38,
"term_years": 30,
"total_interest_paid": 867050.94,
"total_principal_paid": 750000,
"total_repayments": 1617050.94,
"weekly_repayment": 1033.07
}
}Changes
No recorded changes to this operation across all 1 revision of this API.