DEV Community

Rahul Kapoor
Rahul Kapoor

Posted on

How I Developed a GST and Sqft-to-Sq Meter Calculator Using GPT-4

#webdev #programming #ai

How I Developed a GST and Sqft-to-Sq Meter Calculator Using GPT-4

In this post, I’ll walk you through how I developed two simple yet powerful calculators — one for GST (Goods and Services Tax) and another to convert Square Feet to Square Meters — using the power of GPT-4. These tools are helpful for real estate clients, builders, interior designers, and vendors who need instant calculations.

🧠 Why I Built These Calculators

While working on my real estate website and property dealer listings, I realized that clients often:

  • Ask for GST-inclusive prices
  • Need to convert property area from sqft to square meter

Instead of answering repeatedly, I decided to automate it with interactive calculators — and GPT-4 helped me build them quickly and accurately.

🔧 Tools & Technologies Used

  • GPT-4 by OpenAI (for code generation & logic)
  • HTML, CSS & JavaScript (for front-end UI)
  • WordPress (where the calculators were embedded)
  • Optional: PHP for shortcode integration

🔢 1. GST Calculator

✅ Key Features

  • Option to calculate inclusive or exclusive GST
  • Customizable GST rate (5%, 12%, 18%, 28%)
  • Real-time result update

🧮 GST Formula Used 

GST Amount = (Original Amount * GST Rate) / 100
Total (Inclusive) = Original Amount + GST Amount
Enter fullscreen mode Exit fullscreen mode

💡 GPT-4 Prompt Example I Used 

Write me a JavaScript GST calculator with a dropdown to select GST % and two options: include GST or exclude GST from the amount.
Enter fullscreen mode Exit fullscreen mode

✅ Sample Code (Created via GPT-4) 

<label>Amount: <input type="number" id="amount"></label>
<select id="gstRate">
  <option value="5">5%</option>
  <option value="12">12%</option>
  <option value="18">18%</option>
  <option value="28">28%</option>
</select>
<br>
<label><input type="radio" name="type" value="add" checked> Add GST</label>
<label><input type="radio" name="type" value="remove"> Remove GST</label>
<button onclick="calculateGST()">Calculate</button>
<p id="result"></p>

<script>
function calculateGST() {
  const amount = parseFloat(document.getElementById("amount").value);
  const rate = parseFloat(document.getElementById("gstRate").value);
  const type = document.querySelector('input[name="type"]:checked').value;

  let result = "";
  if (type === "add") {
    const gst = (amount * rate) / 100;
    result = `GST: ₹${gst.toFixed(2)}, Total: ₹${(amount + gst).toFixed(2)}`;
  } else {
    const original = amount / (1 + rate / 100);
    const gst = amount - original;
    result = `Base Amount: ₹${original.toFixed(2)}, GST: ₹${gst.toFixed(2)}`;
  }
  document.getElementById("result").innerText = result;
}
</script>
Enter fullscreen mode Exit fullscreen mode

📏 2. Sqft to Sq Meter Converter

✅ Key Features

  • Live conversion as user types
  • Formula-based accuracy
  • Lightweight, mobile-friendly

🧮 Conversion Formula 

1 Sqft = 0.092903 Sq. Meters
Enter fullscreen mode Exit fullscreen mode

💡 GPT-4 Prompt Example 

Create a simple JavaScript calculator to convert square feet to square meters and display results in real time.
Enter fullscreen mode Exit fullscreen mode

✅ Sample Code (Created via GPT-4) 

<label>Square Feet: <input type="number" id="sqft" oninput="convertToSqm()"></label>
<p>Square Meters: <span id="sqm">0</span></p>

<script>
function convertToSqm() {
  const sqft = parseFloat(document.getElementById("sqft").value);
  const sqm = sqft * 0.092903;
  document.getElementById("sqm").innerText = sqm.toFixed(4);
}
</script>
Enter fullscreen mode Exit fullscreen mode

🧪 Testing & Embedding

Once the code was generated, I:

  • Tested it locally in a browser
  • Embedded it in a WordPress page using <script> or created a shortcode
  • Styled it using basic CSS for mobile responsiveness

🎯 Final Outcome

✅ Now visitors on my real estate or service website can:

  • Instantly calculate GST on property cost or services
  • Convert areas from sqft to sqm without needing a separate app or Google

This improves:

  • User experience
  • Engagement
  • Lead conversions (more trust when tools are available)

💡 Lessons Learned

  • GPT-4 is incredibly helpful for rapid prototyping of real-world tools
  • Even if you’re not a coding expert, GPT can guide you step-by-step
  • Small tools can make a big impact on how users interact with your website

🔚 Conclusion

Whether you’re in real estate, e-commerce, or any other business — smart tools like calculators can save time for both you and your users. With GPT-4, building these utilities is faster, cleaner, and even fun!

Written by think4buysale.in Software and ompropertydealer.com

Top comments (0)