Property
Mortgage Calculator
Work out an estimated monthly mortgage payment before you compare lenders.
Inputs
Results
Useful next checks
- Check the inputs before relying on the result.
- Try a second scenario to compare outcomes.
- Read the guide below for context.
Intro
Use this mortgage calculator to estimate the monthly principal and interest repayment on a home loan. Enter the property price, deposit, interest rate, and term to see the approximate payment before comparing lender quotes.
What this mortgage calculator does
The calculator subtracts your deposit from the property price to estimate the loan amount. It then spreads that loan across the term using a standard repayment mortgage formula.
It is best for quick planning questions such as:
- How much might the monthly payment be on a given property price?
- How does a larger deposit change the repayment?
- What happens if the interest rate or term changes?
- How much borrowing is left after the deposit?
How it works
The calculation assumes a fixed interest rate and equal monthly repayments. Each payment includes interest for the month and a repayment of part of the loan balance.
The monthly repayment formula is P * r(1+r)^n / ((1+r)^n - 1). In this formula, P is the loan amount, r is the monthly interest rate, and n is the total number of monthly payments.
If the interest rate is zero, the calculator can treat the payment as the loan amount divided evenly across the number of months.
Example calculation
For a property price of 300,000 with a 60,000 deposit, the starting loan amount is 240,000. Over 30 years, that is 360 monthly payments.
At 5.5% annual interest, the calculator converts the rate to a monthly rate and estimates the principal and interest payment. You can then change the rate, term, or deposit to compare scenarios side by side.
How to use the result
Use the result as an affordability estimate, not as a lender offer. A real mortgage quote may include arrangement fees, valuation fees, mortgage insurance, product fees, taxes, service charges, homeowners insurance, or local property costs.
For a more cautious estimate, try a higher interest rate and a shorter term. For a deposit plan, compare this page with the Savings Goal Calculator.
Assumptions and limitations
- The result estimates principal and interest only.
- It assumes a fixed rate for the full term entered.
- It does not include taxes, insurance, maintenance, fees, or early repayment charges.
- It does not assess lender eligibility, credit score, income multiples, or affordability rules.
- Currency does not change the maths; interpret the values in the currency you entered.
FAQs
- Is this the same as a lender mortgage quote? No. It is a planning estimate based only on the inputs you provide.
- Does a bigger deposit reduce the monthly payment? Yes. A larger deposit lowers the loan amount, which usually lowers the monthly repayment.
- Why does the term affect the payment so much? A longer term spreads the loan over more months, which can reduce the monthly payment but may increase total interest.
- Does this include property tax or insurance? No. Add those separately when budgeting for total housing cost.
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Frequently asked questions
Does this include taxes or insurance?
No. It estimates principal and interest only unless you add those costs separately.
Can I use any currency?
Yes. The maths is the same; interpret the result in the currency you entered.