Laravel Deal with Money in PHP Applications

Typical Behavior of Money in Databases

When dealing with money in a database, one common question arises: How do you save money in a database? Or, How do you define a column for money?

For example, you might define a column like this:

$table->decimal('price', 8, 2);  // 8 is total digits, 2 is decimal digits

Then, when displaying the price, you may use the following:

number_format($product->price, 2);  // Formats the price with 2 decimal places

However, this method can introduce issues. Let me explain why this is not the best approach.

The Issue with Rounding

Let’s walk through an example:

$amount = 107.0277;  // Example: 1 USD = 107.0277 BDT
$quantity = 77;
$product->price = $amount * $quantity;  // Results in 8,241.1329
$product->save();  // In DB, it gets saved as 8,241.14 due to decimal(8, 2)

So, when you retrieve the price from the database:

$price = $product->price;  // 8,241.14
$quantity = 77;
$bdt = $price / $quantity;  // This gives 107.0277922077922

Notice that the result of 107.0277922077922 differs slightly from the original rate of 107.0277. The decimal rounding issue has caused a slight discrepancy.

The Correct Approach

To avoid this rounding issue, you should store the full decimal value in the database. This means you should not restrict the decimal places when saving money.

Here’s how to do it:

$table->decimal('price');  // No restriction on decimal places

By saving the full decimal value, you’ll avoid any rounding problems. Later, when you need to display the price, you can use:

number_format($product->price, 2);  // Format with 2 decimal places when displaying

This way, you store the exact value and only format it when necessary for display.

Conclusion

Storing the full decimal value of money ensures that you avoid rounding issues when doing calculations or currency conversions. By using the approach mentioned above, you'll be able to handle money accurately in your database.

I hope this will be helpful in your future projects. Thank you for reading, and thank you for your continued support! 🙂

Souy Soeng