How to use
- Replace the example inputs with your loan and property figures.
- Select Calculate to update the estimate and any schedule.
- Change one assumption at a time, then compare the result with the earlier scenario.
How this calculation works
The amount borrowed is amortized over the selected term. Each payment includes interest on the outstanding balance and a principal reduction. The calculation is the same fixed-payment mathematics used for a first mortgage, applied only to this additional loan.
M = P × r ÷ [1 − (1 + r)^(−n)]
Worked example
Illustrative inputs — not a quote or a local average.
- Loan amount
- $60,000.00
- Interest rate
- 8 %
- Loan term
- 15 years
Monthly housing estimate: $573.39. Principal & interest: $573.39. Total interest: $43,210.43.
Reading the result
Add the displayed payment to your existing mortgage and property expenses when testing affordability. The interest total belongs to this new loan alone. A shorter repayment term raises the monthly commitment but reduces the time during which interest accrues.
Before acting on the estimate
The tool does not test combined LTV or determine available equity. Use the LTV calculator with both debts and the property value, then ask the lender about its criteria. Home equity is collateral; the arithmetic does not eliminate the repayment risk.

Questions, answered
Does this replace my first mortgage?
This model is for a separate loan. A cash-out refinance replaces the existing first loan instead.
Are fees included?
No. Add quoted transaction costs when comparing offers.