How to Build a Calculator Web App

Quick Answer

To build a calculator web app in Div-idy, simply type a prompt describing the calculator you need. Include what inputs it should ask for (example: loan amount, interest rate, term) and what result it should show. Div-idy generates the UI and the math automatically.

Example prompt: Mortgage calculator

Build a mortgage calculator web app.

Inputs:
- Home price
- Down payment
- Interest rate (APR)
- Loan term (years)
- Property tax (yearly)
- Home insurance (yearly)

Output:
- Monthly payment
- Breakdown (principal + interest, taxes, insurance)
- A clean summary card
- Add validation and format money nicely

Other calculators you can build

• Loan payoff calculator
• ROI / profit calculator
• Budget planner
• BMI calculator
• Calories burned calculator
• Tip calculator
• Unit converter

Prompt templates you can copy

Build a calculator that takes inputs: [A], [B], [C]
and outputs: [Result]. Add a Calculate button, validation,
and a Reset button. Make it look clean and modern.

Create a loan calculator.
Inputs: loan amount, APR, term in years.
Output: monthly payment and total interest.
Auto-format currency and allow the user to change inputs instantly.

Build an ROI calculator web app.
Inputs: initial investment, monthly cost, monthly revenue.
Outputs: monthly profit, yearly profit, ROI %, and break-even month.
Add a simple chart to show profit over time.

Refine your calculator (follow-up prompts)

• Add a chart: “Add a simple chart showing results over time.”
• Make it mobile-friendly: “Stack inputs on mobile and increase button sizes.”
• Add copy/share: “Add a ‘Copy results’ button and a shareable URL query string.”
• Save inputs: “Remember the last inputs using local storage.”

Example follow-up prompt:
"Make this calculator look more professional with better spacing and typography,
but keep all existing functionality exactly the same."

Troubleshooting

• Wrong math? Tell Div-idy what formula you want (or paste the correct formula).
• Inputs allow invalid values? Ask for validation (no negatives, min/max ranges).
• Formatting looks messy? Ask for currency formatting and consistent decimals.