Our methodology
Methodology
The value of a calculator depends on its assumptions. This page explains the methods behind Money Harbour’s tools and how changing information is handled.
General standards
- Calculators publish the main assumptions close to the result.
- Changing rates, costs and thresholds include a checked or reviewed date.
- Examples are labelled as illustrations rather than quotes.
- Commercial relationships do not change calculator outputs.
- Known limitations are stated rather than hidden behind false precision.
Remortgage savings calculator
The calculator uses the standard repayment-mortgage amortisation formula:
Monthly payment = P × r(1+r)ⁿ ÷ ((1+r)ⁿ−1)
Where P is the outstanding balance, r is the monthly interest rate and n is the number of monthly payments remaining.
It calculates the monthly payment for the same balance and remaining term at two annual interest rates, then shows the difference. Two-year and five-year figures multiply that monthly difference by 24 or 60.
What it does not include
Product fees, legal costs, valuations, broker fees, early-repayment charges, changes in balance over time, lender-specific criteria and changes in interest rates during a deal. Those exclusions are why the result is an estimate, not a quote.
Invoice generator
The invoice generator runs in the browser. Line amounts equal quantity multiplied by unit price. Subtotal is the sum of line amounts; optional VAT is calculated at 20%; total due is subtotal plus VAT. The user is responsible for deciding whether VAT applies and for including the legally required business details.
Reviewing changing information
Pages containing rates, tax thresholds or typical market costs display when those figures were checked. A date is not a guarantee that every provider changed at the same moment; links to authoritative guidance should be checked before acting.
Corrections
Methodological or factual corrections can be submitted through the contact page.