Interest-only vs principal & interest: which is right for your investment loan?

The interest-only versus principal-and-interest question comes up in almost every investment loan conversation I have. There is no universally right answer — but there is a right answer for your strategy, and it flows from cash flow, tax position and what you plan to do next.

What interest-only actually means

For a set period — usually up to five years — you pay only the interest on the loan. Your repayments are lower, but the debt itself does not shrink. At the end of the period the loan reverts to principal and interest over the remaining term, which means noticeably higher repayments than if you had paid P&I from day one.

The case for interest-only

• Cash flow. Lower repayments free up money to cover holding costs, fund the next deposit, or simply reduce pressure while a development or renovation completes.
• Deductibility. Interest on an investment loan is generally tax-deductible; principal repayments are not. Investors who still have a home loan on their own house often prefer to direct every spare dollar at that non-deductible debt instead, while keeping the investment loan interest-only.
• Flexibility during a project. In my development work, interest-only during construction and lease-up is standard practice — you match repayments to the phase of the project.

The case for principal & interest

• Price. Lenders charge more for interest-only. The gap moves around, but P&I investment loans are consistently cheaper.
• Equity. Every P&I repayment builds equity you can later borrow against for the next purchase. Interest-only leaves that job entirely to capital growth.
• Serviceability. Some lenders assess an interest-only loan on the shorter P&I period that follows it, which can reduce how much you can borrow across a portfolio.

How I frame the decision with clients

Ask three questions. First, do you still have non-deductible debt on your own home? If yes, interest-only on the investment property while attacking your home loan is often the sensible structure — but it needs to be set up deliberately, ideally with an offset. Second, what does the property need to do: is it a long-term hold where equity build matters, or a staging asset in a bigger plan? Third, can you absorb the repayment step-up when the interest-only period ends — or refinance before it does?

Structure is a moving target

Tax positions change, portfolios grow, and lender policy on interest-only lending tightens and loosens with the regulatory weather. A structure that was right three years ago may be costing you money today. That is why we review investment loan structures as a matter of course, not just rates.

If you are weighing up a purchase — or your interest-only period is coming to an end — book a free assessment and we will model both paths against your actual numbers. General information only, of course: for tax advice specific to you, loop in your accountant, and we are happy to work alongside them.