diff --git a/inc/class-wooviet-vnd-paypal-standard.php b/inc/class-wooviet-vnd-paypal-standard.php
new file mode 100644
index 0000000..6f18f1b
--- /dev/null
+++ b/inc/class-wooviet-vnd-paypal-standard.php
@@ -0,0 +1,109 @@
+<?php
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+/**
+ * The class to add the support for VND when using the Paypal Standard gateway
+ *
+ * @see https://docs.woocommerce.com/document/paypal-standard/
+ *
+ * Reference: https://gist.github.com/vinefruit/3eb76c85707dcd254841
+ *
+ * @author   htdat
+ * @since    1.0
+ *
+ */
+class WooViet_VND_Paypal_Standard {
+
+	/**
+	 * @var int
+	 */
+	protected $exchange_rate_to_vnd;
+	/**
+	 * @var string the curreny will be used
+	 */
+	protected $paypal_currency = 'USD';
+
+	/**
+	 * WooViet_VND_Paypal_Standard constructor.
+	 *
+	 * @param int $exchange_rate_to_vnd
+	 */
+	public function __construct( $exchange_rate_to_vnd = 22770 ) {
+
+		$this->exchange_rate_to_vnd = $exchange_rate_to_vnd;
+
+		// Add VND to the Paypal supported currencies
+		add_filter( 'woocommerce_paypal_supported_currencies', array( $this, 'add_vnd_paypal_valid_currency' ) );
+
+		// Covert VND prices to the selected currency (by default, it's USD) prices before checking out with Paypal Standard
+		add_filter( 'woocommerce_paypal_args', array( $this, 'convert_prices' ), 11 );
+
+		// Add the exchange rate info for this gateway in the checkout page before proceeding in the Paypal pages
+		add_filter( 'option_woocommerce_paypal_settings', array( $this, 'add_exchange_rate_info' ), 11 );
+	}
+
+	/**
+	 * @param $currencies
+	 *
+	 * @return mixed
+	 */
+	public function add_vnd_paypal_valid_currency( $currencies ) {
+		array_push( $currencies, 'VND' );
+
+		return $currencies;
+	}
+
+	/**
+	 * @param $paypal_args
+	 *
+	 * @return mixed
+	 */
+	public function convert_prices( $paypal_args ) {
+		if ( $paypal_args['currency_code'] == 'VND' ) {
+			$paypal_args['currency_code'] = $this->paypal_currency;
+
+			$i = 1;
+
+			while ( isset( $paypal_args[ 'amount_' . $i ] ) ) {
+				$paypal_args[ 'amount_' . $i ] = round( $paypal_args[ 'amount_' . $i ] / $this->exchange_rate_to_vnd, 2 );
+				++ $i;
+			}
+			if ( $paypal_args['shipping_1'] > 0 ) {
+				$paypal_args['shipping_1'] = round( $paypal_args['shipping_1'] / $this->exchange_rate_to_vnd, 2 );
+			}
+
+			if ( $paypal_args['discount_amount_cart'] > 0 ) {
+				$paypal_args['discount_amount_cart'] = round( $paypal_args['discount_amount_cart'] / $this->exchange_rate_to_vnd, 2 );
+			}
+			if ( $paypal_args['tax_cart'] > 0 ) {
+				$paypal_args['tax_cart'] = round( $paypal_args['tax_cart'] / $this->exchange_rate_to_vnd, 2 );
+			}
+		}
+
+		return $paypal_args;
+	}
+
+
+	/**
+	 * @param $value
+	 *
+	 * @return mixed
+	 */
+	public function add_exchange_rate_info( $value ) {
+		if ( ! is_admin() ) {
+
+			$value['description'] .= '<br />';
+			$value['description'] .=
+				sprintf( __( 'The prices will be converted to %1$s in the Paypal pages with the exchange rate %2$s.', 'woocommerce-for-vietnam' ),
+					"<span style='color:red'> $this->paypal_currency</span>",
+					"<span style='color:red'> $this->paypal_currency / VND = $this->exchange_rate_to_vnd</span>"
+				);
+
+		}
+
+		return $value;
+	}
+
+}
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