Context
I designed the loan refinancing flow end-to-end for a banking platform — a multi-step process that lets agents modify loan terms, consolidate loans, and calculate new repayment structures.
This case study focuses on one screen within that flow: the refinancing form, and how I used AI to prototype and test it before finalizing the design.
The focus
The Challenge
The form feeds live calculations — every input on the left instantly updates the repayment breakdown on the right. I wanted to test whether this was intuitive and get feedback on the form overall.
The catch: our users are bankers. They needed to see real, accurate calculations as they interacted with the form.
That meant I needed a fully functional prototype with working math, not a simulation — without going through development.
Process
1. Prompt (ChatGPT) — Described the form logic, uploaded the initial design, defined the research goal. The first prompt is the most important.
2. Prototype (Figma Make) — Pasted the prompt with the design as a base frame. Got a functional prototype with working validation and live calculations on the first try.
3. Interview guide (ChatGPT) — In the same conversation, generated a structured research script focused on calculator visibility and field relationships.
4. Testing — 4 participants (international bankers). Sessions auto-transcribed via Gemini. Feedback documented directly in Figma; transcripts summarized by ChatGPT into Facts vs. Insights.
Design Changes After Research
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Loan cards were information-heavy — users scanned past key details. Stripped each card down to loan number and remaining balance only.
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Users didn't realize they needed to actively select loans — the list read as display, not input. Redesigned to make selection feel like an explicit action.
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Deduction fields came after interest — users expected the opposite. Reordered the form to match their mental model.
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The calculator summary didn't reflect how users think about forgiveness — they expected deductions to appear before interest in the breakdown. Adjusted the order accordingly.
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With multiple loans selected, users lost track of the base amount — they wanted to see the consolidated total before interest was added. Added a sub-summary row for that state.
Before
After
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Interactive Form
Loan refinance form | 2025