How can PHP developers ensure accurate financial calculations, such as calculating total amounts and taxes, to comply with legal requirements?

To ensure accurate financial calculations in PHP, developers should use precise data types like integers or floats, avoid floating-point arithmetic errors by using functions like number_format(), and round results to the necessary decimal places. Additionally, it's essential to keep track of currency conversions and tax rates to comply with legal requirements.

// Example of calculating total amount with taxes
$subtotal = 100.50;
$taxRate = 0.10; // 10%
$taxAmount = $subtotal * $taxRate;
$totalAmount = $subtotal + $taxAmount;

// Round the total amount to 2 decimal places
$totalAmount = number_format($totalAmount, 2);

echo "Subtotal: $subtotal\n";
echo "Tax Amount: $taxAmount\n";
echo "Total Amount: $totalAmount\n";