How to make Simple Interest Calculator in Javascript | Html Simple Interest Calculator for beginners

How to make Simple Interest Calculator in Javascript
Simple Interest Calculator in JavaScript

In this tutorial, we will make a very simple javascript Simple interest calculator using HTML CSS and javascript. If you are a beginner then this tutorial is the best for you what you will learn from this tutorial is .

Note: Make sure you have downloaded the Assests and files for this project Here Link


since we will be building to make this simple interest calculator. You will learn lots of this which will give a great knowledge about DOM manipulation. I will all the list which you will learn during making or following this tutorial.

  • We will learn how to center a container .
  • we will learn how to deal with formula to implement our simple inerest in javascript
  • how to get user input .
  • how to save and manipulate to given specipic place of your output .
  • And many other things which is related with our styling part that will give you an great idea about dom manipulation and some basic element .

To start off we will draw a basic idea of our application which we are be building for this application either you can refer to your notebook or an online software tool Like Figma,Adobe xd, or something else from the marketplace.

It’s not about color staying the elements it’s just a layout refining where you will learn about components of our application .

The Html

Lets start with HTML syntax for the application so that we can define our elements of inputs paragraphs and so on then we will move in javascript and CSS part to make our application working .

<!DOCTYPE html>

    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="style.css">


  <div class="container">
    <h2>Simple Interest</h2>
  <input type="number" id="principal" placeholder="Principal">
    <input type="number" id="rate" placeholder="Rate Of Interest">

    <input type="number" id="time"placeholder="Time in years">
    <div class="result">
      <p>Interest: <span id="interest"></span><br></p> 
      <p>Total Interest: <span id="plus"></span></p>
    <button id="btn" class="button-56" role="button">Submit</button>



Our basic elements are ready let’s move into our styling part where we will learn about how to make our applications looks awesome with our CSS and js for the workability part. Let’s move to our javascript which gives our application winds to calculate our simple interest by using simple logic formula .

The Javascript

  /*Simple Interest Formula = 
    btn.addEventListener("click", () => {
        /*Get input values to the variables */
      let p = parseInt(document.getElementById('principal').value);
      let r = document.getElementById('rate').value;
      let t = document.getElementById('time').value;
      let btn = document.getElementById('btn');
      var interest = (p*r*t)/100;
      document.getElementById('interest').innerHTML = interest;
      var plusInterest = p + interest;
      document.getElementById('plus').innerHTML = plusInterest;

Since we have already done our javascript part lets jump to our styling part so that our app looks amazing and beautiful.


@import url(';200;300;400;500;600;700;800;900&family=Poppins:ital,wght@0,100;0,200;0,300;0,400;0,500;0,600;0,700;0,800;0,900;1,100;1,200;1,300;1,400;1,500;1,600;1,700;1,800;1,900&display=swap');

  padding: 0;
  margin: 0;
  box-sizing: border-box;

  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #3E00AC;
  font-family: 'Poppins', sans-serif;

  width: 550px;
  height: 750px;  
  display: grid;
  place-items: center;
  background: #edf1f4;
  border-radius: 10px;
  border: 3px solid rgb(0, 0, 0);

.container h2 {
  padding-top: 15px;
  font-family: 'Poppins', sans-serif;
  font-weight: 800;
  color: #464646;


.container span{
  font-weight: 700;

.container .result{
  color: #9E9E9E;
  width: 440px;

.container input{
  width: 440px;
  height: 80px;
  background: #edf1f4;
  inset: -5px -5px 5px #fff;
  border-radius: 5px;
  border: 1px solid black;
  outline: none;
  font-size: 20px;
  padding: 24px;

p {
  color: #3E00AC;
  font-size: 17px;
  padding: 10px;

#interest {
  font-size: 20px;
  padding-left: 1rem;
#plus {
  font-size: 20px;
  padding-left: 1rem;

/* CSS */
.button-56 { width: 400px;
  height: 200px;
  align-items: center;
  background-color: #adffc8;
  border: 2px solid #111;
  border-radius: 8px;
  box-sizing: border-box;
  color: rgb(26, 26, 26);
  cursor: pointer;
  display: flex;
  font-family: Inter,sans-serif;
  font-size: 16px;
  height: 68px;
  justify-content: center;
  line-height: 24px;
  max-width: 100%;
  padding: 85rem 25rem;
  position: relative;
  text-align: center;
  text-decoration: none;
  user-select: none;
  -webkit-user-select: none;
  touch-action: manipulation;
  margin-bottom: 1rem;

.button-56:after {
  background-color: #111;
  border-radius: 8px;
  content: "";
  display: block;
  height: 48px;
  left: 0;
  width: 100%;
  position: absolute;
  top: -2px;
  transform: translate(8px, 8px);
  transition: transform .2s ease-out;
  z-index: -1;

.button-56:hover:after {
  transform: translate(0, 0);

.button-56:active {
  background-color: #ffdeda;
  outline: 0;

.button-56:hover {
  outline: 0;

@media (min-width: 768px) {
  .button-56 {
    padding: 0 40px;

After following the whole code of HTML CSS and javascript you will get this kind of interface mention in blow .

Simple Interest Calculator in Javascript  project for beigners

Congratulations! You’ve created a fully functional and styled app. Hopefully, you’ve learned a something new during the whole process! Do comment in the comment box for any suggestion and query .

Downloading Files


Hope you like this article ? Did you enjoy How to make Simple Interest Calculator in Javascript? Let me know in the comment box. Finally, we learn to enjoy and try it on our own.

Happy Coding! ?

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