How much difference can a small rate change make on a mortgage?

Even a small rate change can materially affect monthly repayments and total interest on a large mortgage over a long term, which is why side-by-side comparisons are useful.

Should I compare monthly repayments or total interest?

You should compare both. Lower monthly repayments can look attractive, but total interest and total repayment often tell a more complete story.

Does a loan comparison calculator include lender fees and cashback?

Usually not. It is best used as a rate and repayment comparison, while broker advice can add lender fees, cashback, and structure differences to the real-world decision.

Loan Comparison Calculator

Evaluates how different interest rates impact mortgage payment amounts for informed financial decisions

Loan Amount

Loan Term (Years)

Scenario A

Interest Rate

Scenario B

Interest Rate

Scenario C

Interest Rate

Scenario	Interest Rate	Monthly Payment	Total Interest	Total Repayment
Scenario A	6.00%	$2,998Best	$579,191	$1,079,191
Scenario B	6.50%	$3,160	$637,722	$1,137,722
Scenario C	7.00%	$3,327	$697,544	$1,197,544

Rate Comparison

Difference between highest and lowest rate scenarios:

Monthly payment difference:$329

Total interest difference:$118,354

Even a small difference in interest rates can result in significant savings over the life of a loan. The difference of just 0.5% can mean tens of thousands of dollars in extra interest paid.

Monthly Payment Comparison

Scenario A (6%)$2,998/month

Scenario B (6.5%)$3,160/month

Scenario C (7%)$3,327/month

How to use a loan comparison properly

This kind of comparison is most useful when you want to see how a small rate change affects repayments and total interest over time. It helps turn vague pricing differences into real monthly and long-term cost numbers.

Compare realistic lender rates, not just promotional headlines.
Use the same loan amount and term first, then test structure changes separately.
Look at total interest, not just the lowest monthly repayment.

What this calculator does not show

A loan comparison should be part of the decision, not the whole decision. Real lender offers can also differ on cashback, fees, fixed-term flexibility, and offset or revolving-credit features.

It does not account for refinance costs or break fees.
It does not compare offset, revolving-credit, or split-loan features.
It does not replace lender servicing and credit policy checks.

Loan comparison FAQs

How much difference can 0.5% make on a mortgage?

On a large mortgage over a long term, even a 0.5% rate difference can mean a noticeable change in monthly repayments and tens of thousands of dollars in total interest.

Should I always choose the lowest repayment option?

Not always. A lower repayment can come from stretching the term, which may increase total interest. It is usually better to compare both monthly affordability and lifetime cost.

Can a broker compare more than just interest rates?

Yes. A broker can compare lender policy, cash contributions, structure options, and flexibility so you are not judging the loan on rate alone.

Disclaimer: This calculator provides estimates only and should not be relied upon for financial decisions. Actual loan terms, rates, and eligibility may vary. Please contact a Mortgage Lab adviser for personalised advice.