---
title: "Vehicle loan repayments and what the interest costs"
method: POST
path: "/v1/vehicle-loan"
tags: ["Calculators"]
---

# Vehicle loan repayments and what the interest costs

`POST /v1/vehicle-loan`

## Request

- Base URL: `https://api.calculate.co.nz`
- URL: `https://api.calculate.co.nz/v1/vehicle-loan`
- Auth: API key in header `X-API-Key`

Repayments on a car loan, and the part that is not the payment.

The amortisation is ordinary. What makes a vehicle loan worth its own
endpoint is the context around it. Car finance runs at rates a mortgage
borrower would not recognise, so `interest_share_of_borrowing` regularly
lands above 30% over five years, and that single figure does more to inform
a decision than the monthly payment does.

The term is short, so stretching it barely moves the payment and moves the
total interest a lot. Compare two terms before recommending the longer one.

`fortnightly_equivalent` is the monthly payment converted, because that is
how most people are paid. It is NOT a fortnightly amortisation, which would
clear the loan faster and is a different product; say so if the caller is
comparing.

Read `excludes` before quoting the payment as what someone will pay.
Establishment fees, PPSR registration, mechanical breakdown insurance and
dealer add-ons are usually financed too, so a real contract is higher. A
balloon payment cuts the monthly figure and leaves a lump sum at the end.

## Request body

- VehicleLoanRequest
  - `vehicle_price` number, required: The price of the vehicle.
  - `deposit` number: Cash or trade-in put down up front.
  - `annual_interest_rate_pct` number: Annual rate as a PERCENTAGE, so 12.95 not 0.1295. Car finance commonly runs well above mortgage rates.
  - `term_years` number: Loan term in years.

## Response `200`

Monthly repayment, total interest, and interest as a share of the borrowing.

- VehicleLoanResponse
  - `result` VehicleLoanResult, required
    - `vehicle_price` number, required: Price as given.
    - `deposit` number, required: Deposit as given.
    - `amount_borrowed` number, required: Price less deposit.
    - `annual_interest_rate_pct` number, required: Rate used.
    - `term_years` number, required: Term in years.
    - `term_months` integer, required: Term in whole months.
    - `monthly_repayment` number, required: The contracted monthly payment.
    - `fortnightly_equivalent` number, required: The monthly payment converted, not a fortnightly amortisation. Paying fortnightly would clear the loan faster and is a different product.
    - `weekly_equivalent` number, required: The monthly payment converted to a week.
    - `total_repaid` number, required: Every payment over the term.
    - `total_interest` number, required: What the borrowing costs.
    - `total_cost_including_deposit` number, required: Repayments plus the deposit.
    - `interest_share_of_borrowing` number, required: Interest as a percentage of the amount borrowed. The figure that shows what a long term at a high rate really costs.
    - `deposit_share_of_price` number, required: Deposit as a percentage of the price.
    - `excludes` string[], required: Costs a real contract adds that this does not model.
  - `disclaimer` string, required: Scope and limits of this calculation.

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/calculate/apis/calculate-co-nz-api.md) · [All operations](https://skmtc.dev/calculate/apis/calculate-co-nz-api/llms.txt) · [OpenAPI document](https://skmtc.dev/calculate/apis/calculate-co-nz-api/revisions/aa59a8e76614?raw)