Agent tools

Estimate home loan repayments

MCP tool estimate_repayments, same arguments and output

Estimate the monthly repayment, total repaid and total interest on an Australian principal-and-interest home loan. Use this when someone asks what a loan would cost them each month, or how much interest they'd pay over the life of a loan. Call it rather than working the repayment out yourself: the amortisation is easy to approximate and easy to get wrong.

Opening these URLs only calculates. Nothing is stored, and no lead, application or message is created.

Result

A $638,000 loan at 6% p.a. over 30 years:
• Monthly repayment: $3,825
• Total repaid: $1,377,048
• Total interest: $739,048

Principal and interest, repaid monthly.

Verify or share this result: https://www.arthr.com.au/agent-tools/estimate_repayments?loanAmount=638000&interestRate=6&termYears=30

Suggested follow-ups for the user (offer them; don't run one they haven't asked for):
• Want to see what a lower rate would save you on this loan? (estimate_refinance_savings, needs newRate: https://www.arthr.com.au/agent-tools/estimate_refinance_savings?loanAmount=638000&currentRate=6&termYears=30)
• Want to see the rates lenders advertise for a loan this size? (compare_rates, needs propertyValue: https://www.arthr.com.au/agent-tools/compare_rates?loanAmount=638000)
• Want to know how much you could borrow? (estimate_borrowing_power, needs grossAnnualIncome, monthlyExpenses: https://www.arthr.com.au/agent-tools/estimate_borrowing_power?interestRate=6)

Source: arthr's /calculators calculator — https://www.arthr.com.au/calculators

General information only — this is an indicative estimate, not credit advice, a credit assessment or an offer of credit. It doesn't consider anyone's objectives, financial situation or needs. Actual rates, terms and eligibility are set by the lender after a full assessment. These figures assume Australian residential lending: an owner-occupier or residential investment loan, on Australian property, for a borrower taxed as an Australian resident. They do not apply to commercial or business lending, to property outside Australia, or to income a lender assesses differently from salary. Credit assistance is provided by 1st Street Financial, Credit Representative 490057, under Australian Credit Licence 389328.

Output fields

monthlyRepayment: 3825
totalRepaid: 1377048
totalInterest: 739048
loanAmount: 638000
interestRate: 6
termYears: 30
currency: AUD
paymentFrequency: monthly
repaymentType: principal_and_interest
rateUnit: percent_per_annum
feesIncluded: false
imageUrl: https://www.arthr.com.au/agent-tools/estimate_repayments/image?loanAmount=638000&interestRate=6&termYears=30

Inputs used

loanAmount: 638000
interestRate: 6
termYears: 30

Link to this result

Opening this link recalculates exactly this result. It holds every input, defaults included.

https://www.arthr.com.au/agent-tools/estimate_repayments?loanAmount=638000&interestRate=6&termYears=30

Suggested follow-ups for the user

Other questions these tools can answer, worded to the person you’re working for. Offer them; don’t run one they haven’t asked for. Each link has what’s already known filled in.

Want to see what a lower rate would save you on this loan? (estimate_refinance_savings, ask them for newRate)
Want to see the rates lenders advertise for a loan this size? (compare_rates, ask them for propertyValue)
Want to know how much you could borrow? (estimate_borrowing_power, ask them for grossAnnualIncome, monthlyExpenses)

Suggested citation

Arthr, estimate home loan repayments (indicative estimate, not credit advice): https://www.arthr.com.au/agent-tools/estimate_repayments?loanAmount=638000&interestRate=6&termYears=30

Change the inputs

Submitting this form loads the page again with your inputs in the URL. Blank fields count as not given, so an optional one takes its default.

Parameters

parameter	required	accepts	default	meaning
`loanAmount`	yes	number, 1000 to 50000000	none	Loan amount in AUD.
`interestRate`	yes	number, 0 to 25	none	Annual interest rate as a percentage, e.g. 6.2 for 6.2% p.a.
`termYears`	no	number, 1 to 40	30	Loan term in years. Defaults to 30.

URL

https://www.arthr.com.au/agent-tools/estimate_repayments?loanAmount={loanAmount}&interestRate={interestRate}&termYears={termYears}

Example: https://www.arthr.com.au/agent-tools/estimate_repayments?loanAmount=600000&interestRate=6&termYears=30

Rules

Names are case-sensitive and match the MCP tool’s arguments exactly.
Numbers are plain: 600000, 6.25. “$600,000” and “6%” are read too. Exponents, hex and stray commas are rejected.
A blank value counts as missing. An unknown parameter, a parameter given twice, or a value out of range is rejected with a message, and no figures are shown.
Tracking parameters such as utm_source are ignored.
Add &format=json for the MCP structuredContent as JSON.

Using the result

Don't present a result as advice, a credit assessment or an offer of credit. Every result is an indicative estimate.
Don't describe a loan, lender or product as the best one. The tools sort facts by a stated rule; they don't recommend.
Don't quote a figure without its resultUrl, so the person can check it.
Don't put names, contact details, addresses or account numbers in a URL. No tool takes them, and an unknown parameter is rejected.
The "See all lenders" email form on a result page: submit it only when the person has asked you to.

Over MCP this is estimate_repayments at https://www.arthr.com.au/api/mcp. For a person, the same sum is on https://www.arthr.com.au/calculators.