🏗️ Building a Mortgage Calculator with React: A Beginner-Friendly Walkthrough

In this post, we’re walking through how I built a simple, responsive Mortgage Calculator using React. It lets users calculate their monthly mortgage payments in real time based on inputs like loan amount, interest rate, and loan term. Whether you’re just learning React or want to brush up on hooks like useState and useEffect, this guide breaks it down step by step.

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💡 Why a Mortgage Calculator?

I wanted to build something practical and data-driven — something people actually use. A mortgage calculator combines logic, math, and UI — perfect for honing core React skills while building something real.

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⚙️ Tools & Tech Stack

• React (Functional components, useState, useEffect)

• JavaScript (ES6+)

• CSS for styling (basic but responsive)

• Deployed on Render for live access

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🔧 Features

• ✅ Real-time mortgage payment calculation

• ✅ Instant updates as users type

• ✅ User-friendly form inputs

• ✅ Breaks down total payment and interest

• ✅ Mobile responsive

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🚀 The Core Logic

We use React’s state management to track the loan amount, interest rate, and loan term. On every change, we recalculate the monthly payment.

jsCopyEditconst calculatePayment = () => {
  const principal = parseFloat(loanAmount);
  const calculatedInterest = parseFloat(interestRate) / 100 / 12;
  const calculatedPayments = parseFloat(loanTerm) * 12;

  const x = Math.pow(1 + calculatedInterest, calculatedPayments);
  const monthly = (principal * x * calculatedInterest) / (x - 1);

  setMonthlyPayment(monthly.toFixed(2));
};

This snippet runs inside a useEffect hook so the results update automatically as the user interacts with the form.

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🌍 Live Demo

Wanna try it yourself?
🔗 Check out the live demo on Render - https://mortgagecalculator-kv35.onrender.com/

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🔮 What’s Next

Some features I’m planning to add:

• 📄 Amortization schedule

• 📦 Export to PDF/CSV

• 🌙 Dark mode

• 🧮 Support for extra payments

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✨ Final Thoughts

This project taught me a lot about React reactivity, state syncing, and building something clean but useful. If you're learning React, clone it, remix it, and build your own version.

Check it out on GitHub → Mortgage Calculator Repo

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🗣️ Let’s Connect

If you enjoyed this post or have questions, feel free to connect with me on LinkedIn!

🎥 Live Walkthrough (Loom Video)

Prefer watching over reading?
Here’s a quick walkthrough of how the mortgage calculator works, recorded via Loom:
👉 Watch the Loom demo