How to Design and Create a Calculator with HTML, CSS, and JavaScript
2 mins read

How to Design and Create a Calculator with HTML, CSS, and JavaScript


In this blog post, we will explore how to design and create a calculator with functionality using HTML, CSS, and JavaScript. We will also provide a download button for you to access the source code.

HTML Structure

Let’s start by setting up the HTML structure for our calculator. We will create a container div to hold the calculator, and inside it, we will have a display area and a grid of buttons.

<div class="calculator"><div class="display"><input type="text" id="display" readonly></div><div class="buttons"><button onclick="clearDisplay()">C</button><button onclick="appendToDisplay(7)">7</button><button onclick="appendToDisplay(8)">8</button><button onclick="appendToDisplay(9)">9</button><button onclick="appendToDisplay('+')">+</button><button onclick="appendToDisplay(4)">4</button><button onclick="appendToDisplay(5)">5</button><button onclick="appendToDisplay(6)">6</button><button onclick="appendToDisplay('-')">-</button><button onclick="appendToDisplay(1)">1</button><button onclick="appendToDisplay(2)">2</button><button onclick="appendToDisplay(3)">3</button><button onclick="appendToDisplay('*')">*</button><button onclick="appendToDisplay(0)">0</button><button onclick="appendToDisplay('.')">.</button><button onclick="calculate()">=</button><button onclick="appendToDisplay('/')">/</button></div></div>

CSS Styling

Now let’s add some CSS styling to make our calculator look visually appealing. We will use flexbox to create a grid-like layout for the buttons and apply some basic styling to the display area.

.calculator {width: 300px;background-color: #f2f2f2;border: 1px solid #ccc;border-radius: 5px;padding: 10px;}.display {background-color: #fff;border: 1px solid #ccc;border-radius: 5px;padding: 5px;margin-bottom: 10px;}.buttons {display: flex;flex-wrap: wrap;}button {width: 70px;height: 50px;margin: 5px;background-color: #e6e6e6;border: none;border-radius: 5px;cursor: pointer;}button:hover {background-color: #d9d9d9;}button:active {background-color: #bfbfbf;}

JavaScript Functionality

Now let’s add the JavaScript code to make our calculator functional. We will create several functions to handle different operations such as appending numbers and operators to the display, clearing the display, and calculating the result.

function appendToDisplay(value) {document.getElementById('display').value += value;}function clearDisplay() {document.getElementById('display').value = '';}function calculate() {let expression = document.getElementById('display').value;let result = eval(expression);document.getElementById('display').value = result;}

Download Button

To provide the source code for download, we can add a download button that links to a text file containing the HTML, CSS, and JavaScript code. Here’s an example:

Make sure to create a text file named “calculator-source-code.txt” and include the HTML, CSS, and JavaScript code in it.


By following the steps outlined in this blog post, you should now have a fully functional calculator designed using HTML, CSS, and JavaScript. You can also provide the source code to your users by adding a download button linking to a text file containing the code. Feel free to customize the design and functionality of the calculator to suit your needs.

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