Home calculators
Mortgage repayments, rent conversions, property costs, electricity and household bills, using annualised figures instead of rough weekly × 4 shortcuts.
- Mortgage repayment calculatorEstimate loan repayments, total interest and the principal/interest split for an Australian home loan.
- Mortgage extra repayment calculatorSee how extra monthly repayments cut home-loan interest and years remaining.
- Mortgage offset calculatorEstimate interest saved when a transaction-account balance offsets a home loan.
- Borrowing comparison calculatorCompare two amortising loans on monthly repayment, total interest and total cost.
- Home deposit calculatorTurn a purchase price and deposit percent into the cash needed, loan size and LVR.
- Stamp duty calculatorEstimate transfer (stamp) duty on a property purchase in New South Wales, Victoria or Queensland, from the revenue office's published rates.
- Loan-to-value ratio calculatorCalculate LVR and equity from a loan amount and property value.
- Property deposit goal calculatorSee the monthly savings needed to reach a home deposit target from a price and deposit percent.
- Weekly ↔ monthly rent calculatorConvert Australian rent between weekly, fortnightly, monthly and annual amounts using a 52-week year — not weekly × 4.
- Rent affordability calculatorSee what share of income a rent takes, using 52 weeks and 12 months — not weekly × 4.
- Rent increase calculatorSee the new rent and the extra annual cost after a percentage increase.
- Electricity cost calculatorEstimate what an appliance costs to run from its wattage, how often you use it, and your electricity rate in c/kWh.
Housing is the largest number in most household budgets, and it is also where the sloppiest arithmetic happens. Rent advertised weekly gets multiplied by four instead of by 52 and divided by 12. A repayment is checked at today's interest rate and never at a higher one. An appliance's running cost gets confused with the daily supply charge on the bill.
These tools use the annualised figures that match what you are actually charged, and they show the formula so the difference is visible rather than hidden in a total.
Which tool do you need?
- Converting advertised weekly rent into what you will really pay monthly: use the rent calculator.
- Working out whether a rent is affordable on your income: use the rent affordability calculator, and read its caveats about gross versus after-tax income.
- Pricing a home loan: start with the deposit and LVR calculators, then the mortgage calculator.
- Deciding whether extra repayments or an offset balance is better: compare the extra repayment and offset calculators on the same loan.
- Costing an appliance or working out an energy bill: use the electricity calculator with the rate printed on your own bill.
Common questions
Why is monthly rent not four times the weekly rent?
There are 52 weeks in a year but only 12 months, so a month is about 4.33 weeks. Multiplying weekly rent by four understates the annual cost by roughly four weeks of rent. The correct conversion is weekly × 52 ÷ 12.
Do the mortgage figures include fees and stamp duty?
No. Repayment figures cover principal and interest only. Application fees, ongoing account fees, lender’s mortgage insurance, stamp duty, conveyancing and inspections are all extra, and stamp duty in particular varies by state and by buyer type.
Should the daily supply charge be included when costing an appliance?
No. The supply charge is a fixed daily amount you pay regardless of how much electricity you use, so it belongs in the bill total but never in the marginal cost of running one appliance. Only the usage rate in cents per kilowatt-hour applies there.
What is LVR and why does 20% matter?
Loan-to-value ratio is the loan as a percentage of the property value. A 20% deposit is an 80% LVR, which is the usual line below which lenders skip lenders mortgage insurance. The deposit and LVR guide explains the other costs that sit next to that percentage.
Before you rely on a result
Every calculator on this page shows the formula it used, the assumptions it made and the source of any regulated figure. Results are estimates and not professional advice — the disclaimer explains the limits, and the guides explain the reasoning in more depth.