Serviceability — what is it and how do banks calculate it?

If you’ve been looking for a loan for your home or investment property, you’d have come across the term “serviceability.”

Broadly defined, serviceability is the ability of a borrower to meet loan repayments, based upon the loan amount, the borrower’s income, expenses and other commitments.

This generates an overall figure, known as the debt service ratio — a borrower’s monthly debt expenses as a proportion of monthly income.

Most lenders set a maximum debt service ratio of between 30 and 35 percent.

Having a basic knowledge of how serviceability is calculated can help people to understand and, if necessary, rework their finances in preparation for obtaining a loan for the purchase of owner-occupied or investment property.

Especially in today’s more difficult lending environment.

How is serviceability calculated?


In some industries such as police, fire services and nursing, overtime is an integral part of income and is considered in full for serviceability purposes.

For other professions, a reduced proportion of overtime income is used.

In these cases, the lender acknowledges that the borrower has in fact been paid all of the overtime, but will only apply a reduced amount in calculating serviceability because there is no guarantee that the borrower will continue to earn overtime at the same level if market or employment conditions change.

If an applicant has a second job, the income from it will only be considered if the job has been held continuously for at least one year.

Centrelink benefits, in particular Family Tax Benefit Parts A and B, are considered in most cases where the children are under the age of eleven.

Lenders take into account rental income from investment properties when calculating serviceability.

However, most banks will only use 75% of rental income.

The reasoning for this is that there are costs associated with owning a rental property such as maintenance, management fees and re-letting fees when a tenant vacates.

If an investment property is rented at $1,200.00 per month, 75% of this rental income which is able to be used for serviceability is $900.00.

However, there are a few lenders whose credit policies will use 80, 90 or even 100% of rent.


Existing debt or potential debt (by way of credit cards or lines of credit that are already in place) will lower the amount which is able to be borrowed for a new loan.

In the case of credit cards, most lenders will calculate a minimum repayment obligation of 2.5–3.0% of the approved credit limit.

The lender may require evidence of this debt in the form of account statements in order to confirm monthly repayments.

This applies if there is a balance owing and even where there is a nil balance.

The reasoning for this is that the credit can be accessed to its limit at any time.

For example, if the account has a limit of $15,000, the minimum monthly repayment at 3% will be $450.

Having a $15,000 limit in place will reduce further borrowing capacity for a home loan by approximately $60,000.

Given the significant impact that credit cards can have on applications for new loans, it is advisable to reduce the credit limit(s) to an absolute minimum and can

cel unused cards to improve borrowing power.

Similarly, a line of credit will be taken into account as if it were fully drawn down, even if it isn’t.

In addition, commitments to repaying a car loan, personal loan, HECS and rent will affect home loan borrowing capacity.

The number of dependents a person or couple may have also influences a loan application since there is a financial commitment involved in raising children or caring for other dependents.

Typically, each dependent will reduce the amount able to be borrowed by between $40,000 and $60,000.

Other factors

In calculating repayments for a new loan, lenders will add a margin to the variable rate, to arrive at what is known as the ‘assessment rate’.

Today this margin is around 2.5% or more.

In other words the banks want to know you could repay your debts if interest rates reach 7.5% or 8%.

To make things worse, they also calculate your repayments at the higher rate as if you have a Principal & Interest loan, even if you have an interest only loan.

Now you can see why it’s harder to get finance nowadays — you may have affordability but still not meet the bank’s more strict serviceability criteria.

APRA insists that lenders have a duty of care to ensure that a borrower can meet loan repayments.

Lenders’ serviceability calculators can produce quite different outcomes and so an experienced mortgage broker provides valuable assistance in helping to determine which lender is most suited to each individual circumstance.

The bottom line

Originally published at on February 11, 2018.

Michael Yardney is a #1 bestselling author & a leading expert in the psychology of success and wealth creation Sharing stories on Success, Property & Money