In line with Consumer Affairs Victoria, monthly rent is calculated as follows:
The weekly rental amount is divided by 7 to determine the daily rental rate, then multiplied by 365 (days per year) to determine the yearly rate and finally divided by 12 to determine the monthly rental amount.
For example, a property is advertised as $200 per week, ($200 divided by 7) is $28.57 for the daily rate. The yearly rate ($28.57 x 365 days per year) is then $10,428.05, and the monthly rate ($10,428.05 divided by 12) makes the monthly rent $869.00.
Always round the number to two decimal points (i.e. $$.cc). If your final figure has more than two decimal points round up or down as shown below:
• If the third number after the decimal point is 0 to 4, round down.
• If the third number after the decimal point is 5 to 9, round up.
$180 (weekly rent) ÷ 7 = $25.714285 per day and is rounded down to $25.71
See more info HERE