Interest-only vs principal and interest
Compare short-term cashflow relief against long-term debt reduction before you choose a loan structure.
Introduction
Interest-only loans lower the near-term repayment burden because you are paying only borrowing cost, not principal reduction.
Principal-and-interest repayments feel heavier every month, but they steadily reduce debt and change the payoff profile over time.
Formula and explanation
Interest-only debt cost is the loan balance multiplied by the annual rate. Principal-and-interest repayments amortise the same loan over a fixed term.
That means two properties with the same purchase price and rate can have materially different cashflow depending on the repayment structure you choose.
- Interest-only usually maximizes short-term cashflow.
- Principal-and-interest usually improves equity build over time.
- The best choice depends on how much negative cashflow you can tolerate and how long you plan to hold.
How to interpret it
If the interest-only version barely works, the deal may be too thin to survive even small shocks in rates, rent, or maintenance.
If principal-and-interest still works comfortably, the property has more room to absorb a tougher lending environment.
Common mistakes
Many buyers compare only the monthly repayment and ignore the final balance outcome.
A lower payment today can leave you with a larger debt position and weaker flexibility when the interest-only period ends.
How the calculator maps inputs
Every calculator in this app shows interest-only and principal-and-interest views side by side so you can compare cashflow and ROI from the same assumptions.
The hold calculator adds the long-run payoff row, which is the best way to see how debt structure changes the exit picture.
Related next step
Use the rate sweep to see whether your preferred structure still holds up after a realistic rise in borrowing cost.