NZ Buy vs Rent Calculator

Make informed property decisions

How Our Buy vs Rent Calculator Works

Our Buy vs Rent Calculator uses a year-by-year financial simulation to compare your net wealth outcomes for buying versus renting. Here's how it works:

1. Initial Costs and Assumptions

  • For buying, we start with the house price and subtract the down payment to calculate the mortgage amount.
  • For renting, we begin with the monthly rent you provide.
  • We use the mortgage term you specify for the duration of our calculations.

2. Year-by-Year Calculations

For each year over the mortgage term, we calculate:

Buying Costs:

  • Mortgage payments (calculated using the standard amortization formula)
  • Property taxes (based on the current home value)
  • Maintenance costs (as a percentage of the home value)
  • Home insurance costs
  • One-off purchase costs (stamp duty, legal & conveyancing fees, furnishing & moving). Rather than deducting these from the buyer, we treat them as the renter's opportunity cost: the renter invests the same amount up front, so it compounds against buying over the whole period.
  • We factor in home appreciation, increasing the home's value each year

Renting Costs:

  • Annual rent payments
  • We apply the specified annual rent increase
  • Council Rates is not included for renting, since it is paid by the property owner rather than the tenant. It applies to the buying scenario only.

3. Investment Considerations

We account for the opportunity cost of the down payment and the difference in monthly costs:

  • For the renting scenario, we assume you invest the down payment amount, the one-off purchase costs a buyer would otherwise pay, and any monthly savings compared to buying.
  • Monthly savings are invested throughout the year and grow at the rate you specify for investment returns (with an average 6-month holding period for monthly contributions).
  • The total investment value accumulates year-by-year, compounding at your specified investment return rate.

4. Final Net Worth Comparison

  • For buying, your net worth = current home value minus remaining mortgage balance.
  • For renting, your net worth = total investment value accumulated.
  • We compare these final net worth figures to determine which option builds more wealth.

5. Limitations and Assumptions

It's important to note that this calculator:

  • Assumes constant rates for factors like home appreciation and investment returns, which can vary in reality.
  • Doesn't account for potential tax benefits of homeownership, which can vary by location and individual circumstances.
  • Charges Council Rates to the buying scenario only, since it is owner-paid; costs a tenant may face separately are not modelled.
  • Is a financial comparison tool and doesn't consider non-financial factors that might influence your decision to buy or rent.

This calculator provides a solid foundation for comparing the financial aspects of buying versus renting, but we always recommend consulting with a financial advisor for personalized advice tailored to your specific situation.