Agent tools

Estimate refinance savings

MCP tool estimate_refinance_savings, same arguments and output

Compare an existing home loan rate against a lower one and estimate the monthly and whole-of-term saving. Use this when someone asks whether refinancing is worth it, or what dropping their rate would save them. Call it rather than multiplying the balance by the rate gap: that shortcut ignores the principal in a P&I repayment and overstates the saving. Both rates are arguments — this tool does not quote or assume a market rate.

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

Result

Refinancing $600,000 from 6.6% to 5.9% p.a. over 30 years:
• Now: $3,832 a month
• After: $3,559 a month
• Monthly saving: $273
• Saving over the full term: $98,328

The whole-of-term figure assumes the gap holds for 30 years, and no variable rate does. It also excludes switching costs — discharge, application and settlement fees. estimate_refinance_break_even takes those and returns how long the switch takes to pay for itself.

Verify or share this result: https://www.arthr.com.au/agent-tools/estimate_refinance_savings?loanAmount=600000&currentRate=6.6&newRate=5.9&termYears=30

Suggested follow-ups for the user (offer them; don't run one they haven't asked for):
• Want to know how long switching would take to pay for itself? (estimate_refinance_break_even, needs switchingCosts: https://www.arthr.com.au/agent-tools/estimate_refinance_break_even?loanAmount=600000&currentRate=6.6&newRate=5.9&termYears=30)
• Want to see the rates lenders advertise for your loan? (compare_rates, needs propertyValue: https://www.arthr.com.au/agent-tools/compare_rates?loanAmount=600000)
• Want to know how to leave your current lender? (lookup_discharge_process, needs lender: https://www.arthr.com.au/agent-tools/lookup_discharge_process)

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

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

currentRepayment: 3832
newRepayment: 3559
monthlySaving: 273
totalSaving: 98328
loanAmount: 600000
currentRate: 6.6
newRate: 5.9
termYears: 30
currency: AUD
paymentFrequency: monthly
repaymentType: principal_and_interest
rateUnit: percent_per_annum
switchingCostsIncluded: false
rateHeldForTerm: true
imageUrl: https://www.arthr.com.au/agent-tools/estimate_refinance_savings/image?loanAmount=600000&currentRate=6.6&newRate=5.9&termYears=30

Inputs used

loanAmount: 600000
currentRate: 6.6
newRate: 5.9
termYears: 30 (default)

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_refinance_savings?loanAmount=600000&currentRate=6.6&newRate=5.9&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 know how long switching would take to pay for itself? (estimate_refinance_break_even, ask them for switchingCosts)
Want to see the rates lenders advertise for your loan? (compare_rates, ask them for propertyValue)
Want to know how to leave your current lender? (lookup_discharge_process, ask them for lender)

Suggested citation

Arthr, estimate refinance savings (indicative estimate, not credit advice): https://www.arthr.com.au/agent-tools/estimate_refinance_savings?loanAmount=600000&currentRate=6.6&newRate=5.9&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	Outstanding loan balance in AUD.
`currentRate`	yes	number, 0 to 25	none	The rate they're on now, as a percentage, e.g. 6.8.
`newRate`	yes	number, 0 to 25	none	The rate being compared against, as a percentage, e.g. 6.2.
`termYears`	no	number, 1 to 40	30	Years remaining on the loan. Defaults to 30.

URL

https://www.arthr.com.au/agent-tools/estimate_refinance_savings?loanAmount={loanAmount}&currentRate={currentRate}&newRate={newRate}&termYears={termYears}

Example: https://www.arthr.com.au/agent-tools/estimate_refinance_savings?loanAmount=600000&currentRate=6.6&newRate=5.9

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_refinance_savings at https://www.arthr.com.au/api/mcp. For a person, the same sum is on https://www.arthr.com.au/calculators/savings.