Model your renovation costs and equity impact
Renovation Loan Calculator
Calculate the monthly repayment on a renovation loan and see the estimated impact on your property value and home equity. Model any renovation budget against your current property and mortgage.
Enter your details
Monthly repayment
$594/mo
Over 10 years at 7.5%
Loan amount
$50,000
Total interest
$21,221
Cost of borrowing
Total repaid
$71,221
Estimated new value
$785,000
~70% value add rule
Est. equity after reno
$285,000
Combined LTV
63.7%
After renovation
How this calculator works
A renovation loan lets you borrow against your existing home equity to fund improvements. The two most common options are a home equity loan (a lump sum at a fixed rate) and a home equity line of credit (HELOC, a revolving line at a variable rate). In some countries, construction loans or renovation-specific products are also available.
This calculator models a standard fixed-rate renovation loan: a specific amount borrowed at a set rate, repaid over a chosen term. It shows your monthly repayment, total interest, and estimated impact on your property value and equity.
The 70% value-add assumption (renovations add approximately 70% of their cost in home value) is a conservative industry benchmark. Kitchen and bathroom renovations typically add more; highly custom or structural renovations can add less. Always get an independent valuation before and after major works.
Worked example
- 1Loan amount: NZ$60,000
- 2Monthly payment: NZ$60,000 at 7.5% over 120 months = NZ$712/month
- 3Total repaid: NZ$712 × 120 = NZ$85,440 (NZ$25,440 interest)
- 4Estimated value add: NZ$60,000 × 70% = NZ$42,000 uplift
- 5New home value: NZ$600,000 + NZ$42,000 = NZ$642,000
- 6Equity: NZ$642,000 − NZ$350,000 − NZ$60,000 = NZ$232,000
- 7Combined LTV: (NZ$350,000 + NZ$60,000) / NZ$642,000 = 63.9%
Frequently Asked Questions
Related Calculators
Mortgage Repayment Calculator
Calculate your base mortgage payment before adding renovation costs.
Try calculatorRental Yield Calculator
See how post-renovation rent compares to your updated property value.
Try calculatorRefinance Savings Calculator
Compare a cash-out refinance vs a separate renovation loan.
Try calculatorDisclaimer: Calculations are estimates for general guidance only and do not constitute financial advice. Mortgage rates, LVR restrictions, and lending criteria vary by lender and may be subject to RBNZ requirements. Consult a registered financial adviser before making property decisions.