Embeddable Equipment Finance Calculator

I need a web-based finance calculator that equipment suppliers can drop straight into their sites to display repayment figures for industrial machinery. Think of the look, flow and accuracy of https://finapps.net.au/assetfinance/finance-calculator/—but with the flexibility for me to update interest rates, terms and fees in seconds without touching code.

Core expectations
• Embeddable with a single HTML/JS snippet so any supplier, regardless of platform, can add it to their product pages.
• Professional interface that matches typical B2B machinery websites—clean typography, neutral palette, responsive layout.
• Inputs for price, term, balloon/residual and deposit, with dynamic monthly repayment output.
• A simple “rate management” panel or clearly documented config file where I can adjust rates and default values whenever the market shifts.
• Accurate amortisation math and rounding suitable for Australian asset finance standards.
• Lightweight build with clear, commented source so future tweaks are painless.

Deliverables
1. Working calculator files (HTML/JS/CSS or equivalent framework) ready to embed.
2. Quick-start guide that shows a non-technical supplier how to install and customise.
3. Short change-log template so I can track rate updates over time.

Acceptance criteria
• Drop-in embed on a test page works first time.
• Results match manual calculations across several price/term scenarios.
• Rates editable in under one minute without redeploying the code.

Please respond with a detailed project proposal outlining tech stack, timeline and any similar calculators you have built.