🛠️ pakheritagestore

Credit Card Validator

Validate credit card numbers using the Luhn algorithm and identify card types

ℹ️

For Testing Purposes Only

This tool is designed for development and testing purposes. Never enter real credit card numbers. Use test card numbers provided by payment processors for development.

Card Number Validation

Spaces and dashes will be automatically removed

Validation Results

Enter a credit card number to see validation results

Batch Validation

Batch results will appear here...

Supported Card Types

💳
Visa
Starts with 4
Length: 13, 16, 19 digits
Example: 4532015112830366
🔴
Mastercard
Starts with 5
Length: 16 digits
Example: 5555555555554444
💚
American Express
Starts with 34, 37
Length: 15 digits
Example: 378282246310005
🧡
Discover
Starts with 6
Length: 16 digits
Example: 6011111111111117
💜
Diners Club
Starts with 30, 36, 38
Length: 14 digits
Example: 30569309025904
💛
JCB
Starts with 35
Length: 16 digits
Example: 3530111333300000

About Luhn Algorithm

How It Works

1. Starting from the rightmost digit, double every second digit
2. If doubling results in two digits, add them together
3. Sum all the digits
4. If the total is divisible by 10, the number is valid

Example Calculation

Card: 4532015112830366
Step 1: 4 5 3 2 0 1 5 1 1 2 8 3 0 3 6 6
Step 2: 4 10 3 4 0 2 5 2 1 4 8 6 0 6 6 12
Step 3: 4+1+0+3+4+0+2+5+2+1+4+8+6+0+6+6+1+2=55
Result: Not divisible by 10 (Invalid)

Features

  • ✅ Luhn algorithm validation
  • 🎭 Card type identification
  • 📱 Real-time validation as you type
  • 📦 Batch validation for multiple cards
  • 🔄 Auto-formatting with spaces
  • 📋 Test card numbers included

Use Cases

  • 🧪 Payment form testing
  • 🔧 E-commerce development
  • 📚 Learning payment processing
  • 🛡️ Input validation development
  • 📊 Payment analytics testing
  • 🎯 QA testing scenarios

Example algorithm (days)

// Using date objects in most languages:
days = (date2 - date1).days
Example: Days between 2025-01-01 and 2025-03-01 = 59 days (non-leap year).

6. Days Until

What it does: "Days Until" calculates how many days remain until a target date (a birthday, holiday, event). It is essentially a date-difference from today to a future date but often presented with friendly copy and optional recurrence handling for yearly events.

Features

Example: Today is 2025-09-24 — Days until 2025-12-25 (Christmas) = 92 days.

Putting it all together — Building reliable web calculators

Here are practical tips for developers and product managers building these tools on websites and mobile apps:

Sample HTML form (simplified)

<form id="percentage-form">
<label>Base: <input name="base" type="number" step="any" /></label>
<label>Percentage: <input name="percent" type="number" step="any" /></label>
<button type="submit">Calculate</button>
</form>

Attach client-side JS to compute results instantly and show them inside an accessible result container.

Design & SEO considerations

These calculator pages are highly searchable. Follow these quick SEO tips:

Conclusion

Age, Percentage, Loan, BMI, Date Difference, and Days Until calculators are simple but powerful tools that deliver immediate value. When implemented carefully — with correct formulas, clear UX, accessibility, and privacy considerations — they can significantly improve user engagement and trust. Developers should prefer reliable libraries for date and numeric handling, clearly document assumptions, and provide helpful explanations so users can understand and act on their results.

If you’d like, I can also provide ready-to-use JavaScript snippets for any of the calculators above (for example, a full amortization table script for the Loan Calculator or a BMI widget with unit toggles). Tell me which one you want first and I’ll include a copy-pasteable implementation.

Written as a detailed guide for developers and product teams building small utility calculators for web and mobile. Updated: 2025-09-24.