Not at all! If you can calculate a tip at a restaurant, you can build this. The computer does the hard work.

Do I need to know every state's tax?

Nope! In Step 8, we'll show you how to make a 'Menu' so you don't have to memorize anything.

Will it work on my phone?

Yes! The code we write works in any web browser, on computers and phones.

Build Your Own Sales Tax Calculator (10 Easy Steps)

Hi there! 👋

Have you ever bought a toy for $10, but when you got to the register, they asked for $10.80? That extra money is called Sales Tax.

Today, we are going to build a smart machine that figures out that extra number for us.

Think of coding like cooking a pizza:

HTML is the crust (holds everything).
CSS is the toppings (makes it look yummy).
JavaScript is the oven (makes it hot and ready!).

Let's bake our calculator!

🎯What You Will Learn

✓Create inputs for numbers
✓Do math with code (+ and *)
✓Make drop-down menus
✓Show results on the screen
✓Style it to look professional

Step 1: The Plate (HTML Container) 🍽️

Every meal needs a plate. In code, we call this a "container" or a div. It holds our calculator so it doesn't spill everywhere.

We give it the ID tax-card so we can decorate it later.

html

<div id="tax-card">
  <h2>💰 My Tax Calculator</h2>
  <!-- Ingredients go here -->
</div>

Step 2: The Price Tag (Input) 🏷️

First, we need to ask: "How much does the item cost?" We use an <input> box and tell it to only accept numbers.

html

<label>Price ($):</label>
<input type="number" id="price-input" placeholder="10.00">

Step 3: The Tax Man (Input) 🎩

Next, we need to ask: "How much tax do we have to pay?" This is usually a percentage, like 8%.

html

<label>Tax Rate (%):</label>
<input type="number" id="tax-input" placeholder="8.5">

Step 4: The Cook Button 🍳

We need a button to start cooking! When you click this, it will run a specific set of instructions called calculateTotal.

html

<button onclick="calculateTotal()">Start Calculating</button>

Step 5: The Receipt (Result Area) 🧾

Where do we show the answer? We need a blank space waiting for the result. We'll make two spots: one for the Tax Amount (the extra cost) and one for the Total (what you pay).

html

<div id="result-area">
    <p>Tax: <span id="tax-amount">$0.00</span></p>
    <p>Total: <span id="total-amount">$0.00</span></p>
</div>

Step 6: The Recipe (JavaScript Logic) 📖

Now we teach the computer how to do the math. Here is the recipe:

Grab the Price.
Grab the Tax Rate.
Multiply them to find the tax.
Add the tax to the price to find the total.

javascript

<script>
function calculateTotal() {
    // 1. Get ingredients
    var price = parseFloat(document.getElementById('price-input').value);
    var rate = parseFloat(document.getElementById('tax-input').value);
    
    // Safety check: Did they type numbers?
    if (isNaN(price) || isNaN(rate)) {
        alert("Please type real numbers!");
        return;
    }
    
    // 2. Do the math
    // (Rate / 100) changes "8" into "0.08"
    var taxMoney = price * (rate / 100);
    var finalTotal = price + taxMoney;
    
    // 3. Serve the dish (Show on screen)
    // .toFixed(2) makes it look like money (2 decimal places)
    document.getElementById('tax-amount').innerText = "$" + taxMoney.toFixed(2);
    document.getElementById('total-amount').innerText = "$" + finalTotal.toFixed(2);
}
</script>

Memorizing tax rates is hard. Let's make it easier with a dropdown menu! In HTML, a dropdown is called a <select>.

Add this above your Tax Input from Step 3:

html

<label>Choose a State:</label>
<select id="state-select" onchange="updateRate()">
    <option value="0">Custom Rate</option>
    <option value="7.25">California (7.25%)</option>
    <option value="8.875">New York (8.88%)</option>
    <option value="6.25">Texas (6.25%)</option>
    <option value="6.0">Florida (6.0%)</option>
</select>

Now we need a tiny helper script. When you pick a state from the menu, it should automatically type the number into the Tax Input box for you.

javascript

function updateRate() {
    var menu = document.getElementById('state-select');
    var taxBox = document.getElementById('tax-input');
    
    // If they picked a state, copy the value to the box
    if (menu.value !== "0") {
        taxBox.value = menu.value;
        calculateTotal(); // Auto-calculate!
    }
}

Step 9: Making it Shiny (CSS) ✨

Let's organize our plate. We'll center everything, make the text big, and make the button green like money!

css

<style>
    body { font-family: sans-serif; background: #f0f9ff; }
    
    #tax-card {
        background: white;
        padding: 30px;
        border-radius: 15px;
        max-width: 350px;
        margin: 50px auto;
        box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    }
    
    input, select, button {
        width: 100%;
        padding: 10px;
        margin-bottom: 15px;
        border-radius: 5px;
        border: 1px solid #ccc;
    }
    
    button {
        background-color: #22c55e; /* Money Green */
        color: white;
        font-weight: bold;
        border: none;
        cursor: pointer;
    }
    
    button:hover { background-color: #16a34a; }
    
    #result-area {
        background: #f8fafc;
        padding: 15px;
        border-radius: 10px;
        border: 2px dashed #ddd;
    }
</style>

Step 10: The Whole Enchilada (Full Code) 🌯

Here is the complete code. You can save this as tax-calculator.html and use it for your next shopping trip!

html

<!DOCTYPE html>
<html>
<head>
    <title>My Tax Calculator</title>
    <style>
        body { background: #e0f2fe; font-family: 'Segoe UI', sans-serif; display: flex; justify-content: center; min-height: 100vh; align-items: center; margin: 0; }
        .card {
            background: white;
            padding: 2rem;
            border-radius: 1rem;
            box-shadow: 0 20px 25px -5px rgba(0,0,0,0.1);
            width: 100%;
            max-width: 320px;
        }
        h2 { color: #0369a1; text-align: center; margin-top: 0; }
        
        label { font-weight: 600; font-size: 0.9rem; color: #475569; display: block; margin-bottom: 0.5rem; }
        input, select {
            width: 100%;
            padding: 0.75rem;
            border: 2px solid #e2e8f0;
            border-radius: 0.5rem;
            margin-bottom: 1rem;
            box-sizing: border-box;
            font-size: 1rem;
        }
        
        button {
            width: 100%;
            padding: 0.75rem;
            background: #0ea5e9;
            color: white;
            border: none;
            border-radius: 0.5rem;
            font-size: 1rem;
            font-weight: bold;
            cursor: pointer;
            transition: 0.2s;
        }
        button:hover { background: #0284c7; transform: translateY(-1px); }
        
        .result-box {
            margin-top: 1.5rem;
            padding: 1rem;
            background: #f0f9ff;
            border-radius: 0.5rem;
            border: 2px dashed #bae6fd;
        }
        .row { display: flex; justify-content: space-between; margin-bottom: 0.5rem; color: #64748b; }
        .total-row { display: flex; justify-content: space-between; font-weight: bold; font-size: 1.25rem; color: #0c4a6e; border-top: 2px solid #bae6fd; padding-top: 0.5rem; margin-top: 0.5rem; }
    </style>
</head>
<body>

<div class="card">
    <h2>💸 Tax Calculator</h2>
    
    <label>Item Price ($)</label>
    <input type="number" id="price" placeholder="0.00">
    
    <label>Select State</label>
    <select id="state" onchange="updateRate()">
        <option value="0">-- Custom Rate --</option>
        <option value="7.25">California (7.25%)</option>
        <option value="8.875">New York (8.88%)</option>
        <option value="6.25">Texas (6.25%)</option>
        <option value="6.0">Florida (6.0%)</option>
        <option value="10.0">Easy Math (10%)</option>
    </select>
    
    <label>Tax Rate (%)</label>
    <input type="number" id="rate" placeholder="0.0">
    
    <button onclick="calculate()">Calculate Total</button>
    
    <div class="result-box">
        <div class="row">
            <span>Subtotal:</span>
            <span id="res-price">$0.00</span>
        </div>
        <div class="row">
            <span>Tax Amount:</span>
            <span id="res-tax">$0.00</span>
        </div>
        <div class="total-row">
            <span>TOTAL:</span>
            <span id="res-total">$0.00</span>
        </div>
    </div>
</div>

<script>
    function updateRate() {
        var menu = document.getElementById('state');
        if(menu.value != "0") {
            document.getElementById('rate').value = menu.value;
            calculate();
        }
    }

    function calculate() {
        var price = parseFloat(document.getElementById('price').value) || 0;
        var rate = parseFloat(document.getElementById('rate').value) || 0;
        
        var tax = price * (rate / 100);
        var total = price + tax;
        
        document.getElementById('res-price').innerText = "$" + price.toFixed(2);
        document.getElementById('res-tax').innerText = "$" + tax.toFixed(2);
        document.getElementById('res-total').innerText = "$" + total.toFixed(2);
    }
    
    // Auto-calculate when typing
    document.getElementById('price').addEventListener('input', calculate);
    document.getElementById('rate').addEventListener('input', calculate);
</script>

</body>
</html>

Conclusion

Great job! 🍎

You've built your own helper tool. You learned how to take inputs, do math with them, and show the result nicely.

Now, whenever you see a price tag, you can use your app to know exactly how much you'll pay at the register!

Try the Advanced Tax Tool »

Hi there! 👋

Have you ever bought a toy for $10, but when you got to the register, they asked for $10.80? That extra money is called Sales Tax.

Today, we are going to build a smart machine that figures out that extra number for us.

Think of coding like cooking a pizza:

HTML is the crust (holds everything).
CSS is the toppings (makes it look yummy).
JavaScript is the oven (makes it hot and ready!).

Let's bake our calculator!

🎯What You Will Learn

✓Create inputs for numbers
✓Do math with code (+ and *)
✓Make drop-down menus
✓Show results on the screen
✓Style it to look professional

Step 1: The Plate (HTML Container) 🍽️

Every meal needs a plate. In code, we call this a "container" or a div. It holds our calculator so it doesn't spill everywhere.

We give it the ID tax-card so we can decorate it later.

html

<div id="tax-card">
  <h2>💰 My Tax Calculator</h2>
  <!-- Ingredients go here -->
</div>

Step 2: The Price Tag (Input) 🏷️

First, we need to ask: "How much does the item cost?" We use an <input> box and tell it to only accept numbers.

html

<label>Price ($):</label>
<input type="number" id="price-input" placeholder="10.00">

Step 3: The Tax Man (Input) 🎩

Next, we need to ask: "How much tax do we have to pay?" This is usually a percentage, like 8%.

html

<label>Tax Rate (%):</label>
<input type="number" id="tax-input" placeholder="8.5">

Step 4: The Cook Button 🍳

We need a button to start cooking! When you click this, it will run a specific set of instructions called calculateTotal.

html

<button onclick="calculateTotal()">Start Calculating</button>

Step 5: The Receipt (Result Area) 🧾

Where do we show the answer? We need a blank space waiting for the result. We'll make two spots: one for the Tax Amount (the extra cost) and one for the Total (what you pay).

html

<div id="result-area">
    <p>Tax: <span id="tax-amount">$0.00</span></p>
    <p>Total: <span id="total-amount">$0.00</span></p>
</div>

Step 6: The Recipe (JavaScript Logic) 📖

Now we teach the computer how to do the math. Here is the recipe:

Grab the Price.
Grab the Tax Rate.
Multiply them to find the tax.
Add the tax to the price to find the total.

javascript

<script>
function calculateTotal() {
    // 1. Get ingredients
    var price = parseFloat(document.getElementById('price-input').value);
    var rate = parseFloat(document.getElementById('tax-input').value);
    
    // Safety check: Did they type numbers?
    if (isNaN(price) || isNaN(rate)) {
        alert("Please type real numbers!");
        return;
    }
    
    // 2. Do the math
    // (Rate / 100) changes "8" into "0.08"
    var taxMoney = price * (rate / 100);
    var finalTotal = price + taxMoney;
    
    // 3. Serve the dish (Show on screen)
    // .toFixed(2) makes it look like money (2 decimal places)
    document.getElementById('tax-amount').innerText = "$" + taxMoney.toFixed(2);
    document.getElementById('total-amount').innerText = "$" + finalTotal.toFixed(2);
}
</script>

Memorizing tax rates is hard. Let's make it easier with a dropdown menu! In HTML, a dropdown is called a <select>.

Add this above your Tax Input from Step 3:

html

<label>Choose a State:</label>
<select id="state-select" onchange="updateRate()">
    <option value="0">Custom Rate</option>
    <option value="7.25">California (7.25%)</option>
    <option value="8.875">New York (8.88%)</option>
    <option value="6.25">Texas (6.25%)</option>
    <option value="6.0">Florida (6.0%)</option>
</select>

Now we need a tiny helper script. When you pick a state from the menu, it should automatically type the number into the Tax Input box for you.

javascript

function updateRate() {
    var menu = document.getElementById('state-select');
    var taxBox = document.getElementById('tax-input');
    
    // If they picked a state, copy the value to the box
    if (menu.value !== "0") {
        taxBox.value = menu.value;
        calculateTotal(); // Auto-calculate!
    }
}

Step 9: Making it Shiny (CSS) ✨

Let's organize our plate. We'll center everything, make the text big, and make the button green like money!

css

<style>
    body { font-family: sans-serif; background: #f0f9ff; }
    
    #tax-card {
        background: white;
        padding: 30px;
        border-radius: 15px;
        max-width: 350px;
        margin: 50px auto;
        box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    }
    
    input, select, button {
        width: 100%;
        padding: 10px;
        margin-bottom: 15px;
        border-radius: 5px;
        border: 1px solid #ccc;
    }
    
    button {
        background-color: #22c55e; /* Money Green */
        color: white;
        font-weight: bold;
        border: none;
        cursor: pointer;
    }
    
    button:hover { background-color: #16a34a; }
    
    #result-area {
        background: #f8fafc;
        padding: 15px;
        border-radius: 10px;
        border: 2px dashed #ddd;
    }
</style>

Step 10: The Whole Enchilada (Full Code) 🌯

Here is the complete code. You can save this as tax-calculator.html and use it for your next shopping trip!

html

<!DOCTYPE html>
<html>
<head>
    <title>My Tax Calculator</title>
    <style>
        body { background: #e0f2fe; font-family: 'Segoe UI', sans-serif; display: flex; justify-content: center; min-height: 100vh; align-items: center; margin: 0; }
        .card {
            background: white;
            padding: 2rem;
            border-radius: 1rem;
            box-shadow: 0 20px 25px -5px rgba(0,0,0,0.1);
            width: 100%;
            max-width: 320px;
        }
        h2 { color: #0369a1; text-align: center; margin-top: 0; }
        
        label { font-weight: 600; font-size: 0.9rem; color: #475569; display: block; margin-bottom: 0.5rem; }
        input, select {
            width: 100%;
            padding: 0.75rem;
            border: 2px solid #e2e8f0;
            border-radius: 0.5rem;
            margin-bottom: 1rem;
            box-sizing: border-box;
            font-size: 1rem;
        }
        
        button {
            width: 100%;
            padding: 0.75rem;
            background: #0ea5e9;
            color: white;
            border: none;
            border-radius: 0.5rem;
            font-size: 1rem;
            font-weight: bold;
            cursor: pointer;
            transition: 0.2s;
        }
        button:hover { background: #0284c7; transform: translateY(-1px); }
        
        .result-box {
            margin-top: 1.5rem;
            padding: 1rem;
            background: #f0f9ff;
            border-radius: 0.5rem;
            border: 2px dashed #bae6fd;
        }
        .row { display: flex; justify-content: space-between; margin-bottom: 0.5rem; color: #64748b; }
        .total-row { display: flex; justify-content: space-between; font-weight: bold; font-size: 1.25rem; color: #0c4a6e; border-top: 2px solid #bae6fd; padding-top: 0.5rem; margin-top: 0.5rem; }
    </style>
</head>
<body>

<div class="card">
    <h2>💸 Tax Calculator</h2>
    
    <label>Item Price ($)</label>
    <input type="number" id="price" placeholder="0.00">
    
    <label>Select State</label>
    <select id="state" onchange="updateRate()">
        <option value="0">-- Custom Rate --</option>
        <option value="7.25">California (7.25%)</option>
        <option value="8.875">New York (8.88%)</option>
        <option value="6.25">Texas (6.25%)</option>
        <option value="6.0">Florida (6.0%)</option>
        <option value="10.0">Easy Math (10%)</option>
    </select>
    
    <label>Tax Rate (%)</label>
    <input type="number" id="rate" placeholder="0.0">
    
    <button onclick="calculate()">Calculate Total</button>
    
    <div class="result-box">
        <div class="row">
            <span>Subtotal:</span>
            <span id="res-price">$0.00</span>
        </div>
        <div class="row">
            <span>Tax Amount:</span>
            <span id="res-tax">$0.00</span>
        </div>
        <div class="total-row">
            <span>TOTAL:</span>
            <span id="res-total">$0.00</span>
        </div>
    </div>
</div>

<script>
    function updateRate() {
        var menu = document.getElementById('state');
        if(menu.value != "0") {
            document.getElementById('rate').value = menu.value;
            calculate();
        }
    }

    function calculate() {
        var price = parseFloat(document.getElementById('price').value) || 0;
        var rate = parseFloat(document.getElementById('rate').value) || 0;
        
        var tax = price * (rate / 100);
        var total = price + tax;
        
        document.getElementById('res-price').innerText = "$" + price.toFixed(2);
        document.getElementById('res-tax').innerText = "$" + tax.toFixed(2);
        document.getElementById('res-total').innerText = "$" + total.toFixed(2);
    }
    
    // Auto-calculate when typing
    document.getElementById('price').addEventListener('input', calculate);
    document.getElementById('rate').addEventListener('input', calculate);
</script>

</body>
</html>

Conclusion

Great job! 🍎

You've built your own helper tool. You learned how to take inputs, do math with them, and show the result nicely.

Now, whenever you see a price tag, you can use your app to know exactly how much you'll pay at the register!

Try the Advanced Tax Tool »

Build Your Own Sales Tax Calculator (10 Easy Steps)

Step 1: The Plate (HTML Container) 🍽️

Step 2: The Price Tag (Input) 🏷️

Step 3: The Tax Man (Input) 🎩

Step 4: The Cook Button 🍳

Step 5: The Receipt (Result Area) 🧾

Step 6: The Recipe (JavaScript Logic) 📖

Step 8: Connecting the Menu 🔗

Step 9: Making it Shiny (CSS) ✨

Step 10: The Whole Enchilada (Full Code) 🌯

Conclusion

FastTools Team

Build Your Own Sales Tax Calculator (10 Easy Steps)

Step 1: The Plate (HTML Container) 🍽️

Step 2: The Price Tag (Input) 🏷️

Step 3: The Tax Man (Input) 🎩

Step 4: The Cook Button 🍳

Step 5: The Receipt (Result Area) 🧾

Step 6: The Recipe (JavaScript Logic) 📖

Step 8: Connecting the Menu 🔗

Step 9: Making it Shiny (CSS) ✨

Step 10: The Whole Enchilada (Full Code) 🌯

Conclusion

FastTools Team

Finance

Health

Education

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Social

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Developer

Festivals

Step 1: The Plate (HTML Container) 🍽️

Step 2: The Price Tag (Input) 🏷️

Step 3: The Tax Man (Input) 🎩

Step 4: The Cook Button 🍳

Step 5: The Receipt (Result Area) 🧾

Step 6: The Recipe (JavaScript Logic) 📖

Step 7: The "State" Menu (Dropdown) 🗺️

Step 8: Connecting the Menu 🔗

Step 9: Making it Shiny (CSS) ✨

Step 10: The Whole Enchilada (Full Code) 🌯

Conclusion

FastTools Team

Step 1: The Plate (HTML Container) 🍽️

Step 2: The Price Tag (Input) 🏷️

Step 3: The Tax Man (Input) 🎩

Step 4: The Cook Button 🍳

Step 5: The Receipt (Result Area) 🧾

Step 6: The Recipe (JavaScript Logic) 📖

Step 7: The "State" Menu (Dropdown) 🗺️

Step 8: Connecting the Menu 🔗

Step 9: Making it Shiny (CSS) ✨

Step 10: The Whole Enchilada (Full Code) 🌯

Conclusion

FastTools Team