Setting Minimum Checkout Requirements in WooCommerce

Chances are that you want to set some kind of minimum requirements on your WooCommerce store before your customers checkout. What follows is a guide on how to set these requirements and restrictions, without needing to use any plugins at all:

• Setting A Minimum Weight Requirement Per Order
• Setting A Minimum Number Of Products Required Per Order
• Setting A Minimum Quantity Per Product
• Setting A Minimum Dollar Amount Per Order

Methods Used In This Article

There is always more than one way of setting minimum requirements in WooCommerce; the results might even be identical. But I consider the methods described below to be the right (or better) way of doing it. Any suggestions on how you accomplish these tasks or further improvements are always welcome and received well.

The following code has been tested in the latest versions available for WordPress (3.9.1) and WooCommerce (2.1.12). We’ll be using the dummy data provided for WooCommerce when you install the plugin. The code should go in your theme’s functions.php file and is heavily commented so it’s easier to follow and/or modify if needed.

We are going to be using the woocommerce_check_cart_items action provided by WooCommerce to run our functions and execute our code. Visit the following link for a complete list of WooCommerce actions and filters, also known as hooks.

Setting A Minimum Weight Requirement Per Order

It is often useful to restrict your customer(s) from completing the checkout process without having met a minimum weight requirement. Minium weight requirements can help make your shipping costs more manageable, and the shipping process more streamlined. Don’t forget to change the minimum weight requirement to whatever works best for you, and keep in mind that weight is calculated in whatever weight unit you have set under WooCommerce -> Settings -> Products.

// Set a minimum weight requirement before checking out
add_action( 'woocommerce_check_cart_items', 'spyr_set_weight_requirements' );
function spyr_set_weight_requirements() {
	// Only run in the Cart or Checkout pages
	if( is_cart() || is_checkout() ) {
		global $woocommerce;
		// Set the minimum weight before checking out
		$minimum_weight = 25;
		// Get the Cart's content total weight
		$cart_contents_weight = WC()->cart->cart_contents_weight;
		// Compare values and add an error is Cart's total weight
	    // happens to be less than the minimum required before checking out.
		// Will display a message along the lines of
		// A Minimum Weight of 25kg is required before checking out. (Cont. below)
		// Current cart weight: 12.5kg
		if( $cart_contents_weight < $minimum_weight  ) {
			// Display our error message
			wc_add_notice( sprintf('<strong>A Minimum Weight of %s%s is required before checking out.</strong>'
				. '<br />Current cart weight: %s%s',
				$minimum_weight,
				get_option( 'woocommerce_weight_unit' ),
				$cart_contents_weight,
				get_option( 'woocommerce_weight_unit' ),
				get_permalink( wc_get_page_id( 'shop' ) )
				),
			'error'	);
		}
	}
}

Setting A Minimum Number Of Products Required Per Order

Another valid scenario is setting a minimum number of products that have to be ordered at a time before allowing the customer to fully pay for his order and shipped. Change ’20’ to whatever works best for your needs. As in the previous example, you want to make sure that you only run this code on the cart and checkout pages. This is we use is_cart() and is_checkout(), which return ‘true’ whenever we are on those two specific pages. Learn more about WooCommerce conditionals Tags.

// Set a minimum number of products requirement before checking out
add_action( 'woocommerce_check_cart_items', 'spyr_set_min_num_products' );
function spyr_set_min_num_products() {
	// Only run in the Cart or Checkout pages
	if( is_cart() || is_checkout() ) {
		global $woocommerce;

		// Set the minimum number of products before checking out
		$minimum_num_products = 20;
		// Get the Cart's total number of products
		$cart_num_products = WC()->cart->cart_contents_count;

		// Compare values and add an error is Cart's total number of products
	    // happens to be less than the minimum required before checking out.
		// Will display a message along the lines of
		// A Minimum of 20 products is required before checking out. (Cont. below)
		// Current number of items in the cart: 6	
		if( $cart_num_products < $minimum_num_products ) {
			// Display our error message
	        wc_add_notice( sprintf( '<strong>A Minimum of %s products is required before checking out.</strong>' 
	        	. '<br />Current number of items in the cart: %s.',
	        	$minimum_num_products,
	        	$cart_num_products ),
	        'error' );
		}
	}
}

Setting A Minimum Quantity Per Product

Setting a minimum quantity per product is a common requirement for WooCommerce stores, specially if you are selling wholesale. Setting a minimum quantity will restrict your customer(s) from purchasing a specific product in lesser quantities. For us to check for the minimum quantities, we need to loop through every single product in the cart and check it against our minimum quantity per product requirements set in place.

To set these restrictions, you need to create an array which holds your rules/restrictions inside another array. Be careful when editing this array, and make sure that all code is entered accurately in order to prevent errors and unexpected results. The format you need to use is as follows:

// Product Id and Min. Quantities per Product
// id = Product ID
// min = Minimum quantity
$product_min_qty = array( 
	array( 'id' => 47, 'min' => 100 ),
	array( 'id' => 37, 'min' => 100 ),
	array( 'id' => 34, 'min' => 100 ),
	array( 'id' => 31, 'min' => 100 ),
);

Here is where the magic happens.

// Set minimum quantity per product before checking out
add_action( 'woocommerce_check_cart_items', 'spyr_set_min_qty_per_product' );
function spyr_set_min_qty_per_product() {
	// Only run in the Cart or Checkout pages
	if( is_cart() || is_checkout() ) {	
		global $woocommerce;

		// Product Id and Min. Quantities per Product
		$product_min_qty = array( 
			array( 'id' => 47, 'min' => 100 ),
			array( 'id' => 37, 'min' => 100 ),
			array( 'id' => 34, 'min' => 100 ),
			array( 'id' => 31, 'min' => 100 ),
		);

		// Will increment
		$i = 0;
		// Will hold information about products that have not
		// met the minimum order quantity
		$bad_products = array();

		// Loop through the products in the Cart
		foreach( $woocommerce->cart->cart_contents as $product_in_cart ) {
			// Loop through our minimum order quantities per product
			foreach( $product_min_qty as $product_to_test ) {
				// If we can match the product ID to the ID set on the minimum required array
				if( $product_to_test['id'] == $product_in_cart['product_id'] ) {
					// If the quantity required is less than than the quantity in the cart now
					if( $product_in_cart['quantity'] < $product_to_test['min'] ) {
						// Get the product ID
						$bad_products[$i]['id'] = $product_in_cart['product_id'];
						// Get the Product quantity already in the cart for this product
						$bad_products[$i]['in_cart'] = $product_in_cart['quantity'];
						// Get the minimum required for this product
						$bad_products[$i]['min_req'] = $product_to_test['min'];
					}
				}
			}
			// Increment $i
			$i++;
		}

		// Time to build our error message to inform the customer
		// About the minimum quantity per order.
		if( is_array( $bad_products) && count( $bad_products ) > 1 ) {
			// Lets begin building our message
			$message = '<strong>A minimum quantity per product has not been met.</strong><br />';
			foreach( $bad_products as $bad_product ) {
				// Append to the current message
				$message .= get_the_title( $bad_product['id'] ) .' requires a minimum quantity of '
						 . $bad_product['min_req'] 
						 .'. You currently have: '. $bad_product['in_cart'] .'.<br />';
			}
			wc_add_notice( $message, 'error' );
		}
	}
}

Setting A Minimum Dollar Amount Per Order

Last but not least, you may want to set a minimum dollar amount that must be spent before your customer is allowed to checkout. Please note that we are calculating the total value using the subtotal, before shipping and taxes are added to the final order total.

// Set a minimum dollar amount per order
add_action( 'woocommerce_check_cart_items', 'spyr_set_min_total' );
function spyr_set_min_total() {
	// Only run in the Cart or Checkout pages
	if( is_cart() || is_checkout() ) {
		global $woocommerce;

		// Set minimum cart total
		$minimum_cart_total = 10;

		// Total we are going to be using for the Math
		// This is before taxes and shipping charges
		$total = WC()->cart->subtotal;
		
		// Compare values and add an error is Cart's total
	    // happens to be less than the minimum required before checking out.
		// Will display a message along the lines of
		// A Minimum of 10 USD is required before checking out. (Cont. below)
		// Current cart total: 6 USD 
		if( $total <= $minimum_cart_total  ) {
			// Display our error message
			wc_add_notice( sprintf( '<strong>A Minimum of %s %s is required before checking out.</strong>'
				.'<br />Current cart\'s total: %s %s',
				$minimum_cart_total,
				get_option( 'woocommerce_currency'),
				$total,
				get_option( 'woocommerce_currency') ),
			'error' );
		}
	}
}

Conclusion

Are you can see, WooCommerce allows you to use actions and filters to change the normal checkout process. All stores are different and being able to set these restrictions when needed is crucial. For us developers, who need to accomplish tasks like these, knowing how to do it is vital.

Thanks for reading, comments or suggestions on how to improve the code are always welcome. If you have ideas for a specific WooCommerce modification, don’t be shy and post a link to it in the comments for discussion.