← Building library

Building library · Borrowing and finance

Interest only, or principal
and interest?

Two ways to repay an investment loan, and why the right one changes with the stage you are at.

· Written 10 October 2026 · Checked 11 October 2026

Three panels: a cloud following a person, rowers at the oars of a galley, and a helper growing into a master.
Some debt follows you, some keeps you rowing, and some ends up giving the orders.
AI illustration of Nicholas Lockhart
Listen to Nicholas read this article
Read by an AI version of Nicholas’s voice, from the article he wrote.
4 min

Interest only or principal and interest? For an investment loan, it is one of the first choices you make with a lender. Each suits a different stage of investing, and I have used both over the years.

The difference

Interest onlyPrincipal and interest
Each repayment paysOnly the interestThe interest and part of the loan
The loan over timeStays the sameFalls with every repayment
RepaymentsLower, for a set periodHigher, from the start
After the set periodUsually reverts, and repayments riseNo change
The rateOften higherOften lower

Why investors choose interest only

Lower repayments leave more cash each week, which can help someone carry a property or save towards the next one. While you are building, any rise in the property’s value lowers the loan-to-value ratio, even with an interest-only loan. Interest on an investment loan is usually deductible. Interest on your home loan is not, which is why some investors put their spare cash against the home loan first.

Why investors choose principal and interest

Principal and interest builds equity through repayments as well as value, and the rate is often lower. Lenders see it as less risky. Every repayment brings you closer to owning the property outright, and that counts for more as retirement nears.

The stage you are at

I see this choice as a question of stage. While you are building, the focus is holding the property while its value grows, and keeping cash in hand. As retirement comes closer, the focus turns to income, and debt that served you while building becomes a weight. I have sat with people who reached retirement still on interest-only loans, having made minimal repayments to keep their cash for more property, with no plan for the debt. Seeing that coming ten years ahead leaves room to act. A broker can give you a view of your own loans. Home Buyers Club is run by my son, James.

Who interest only does not suit

Interest only does not suit someone who would spend the cash it frees rather than put it to work, or who could not carry the higher repayments when the interest-only period ends. Lenders can decline to extend it, so the day it stops belongs in the plan from the start. The repayment type is not a detail. It is part of the plan, and it changes when the plan does.

The right repayment type depends on where you are with your whole portfolio, years ahead. To see which suits yours, book a first conversation. It costs nothing.

Nicholas Lockhart

A broker can explain the loan options open to you.

Start with your position →

Your view helps the next person find clarity and confidence. Leave a Google review.

Leave a review

Get a feel for us first.A mentor with experience since 1997, from the first conversation to the keys and beyond.

Connect with Nicholas →

Clarity first. Confidence follows. The MRD way.