Unit price

Polish law requires online stores to show the unit price of a product - e.g. price per kilogram, liter or meter. Polski for WooCommerce adds this information automatically on the product page, in listings and in the cart.

When is a unit price required

The obligation to provide unit prices applies to products sold by weight, volume or length. In practice this includes:

• food products (price per kg or liter)
• cosmetics and cleaning products (price per 100 ml or liter)
• construction materials (price per running meter or square meter)
• bulk products (price per kg)

The unit price must be visible everywhere the product price is presented - on the product page, in search results, in price comparisons and in the cart.

Configuration

Go to WooCommerce > Settings > Polski > Prices and enable the unit price module. After activation, a new section will appear in the product editor under the “General” tab.

Fields in the product editor

Field	Description	Example
Base quantity	Product quantity in the package	500
Base unit	Product unit of measurement	g
Reference quantity	Reference quantity for the unit price	1
Reference unit	Unit for which the price is given	kg

For a product weighing 500 g with a price of 12.99 PLN, the plugin will automatically calculate the unit price as 25.98 PLN/kg.

Supported units

The plugin supports the following units of measurement:

• Weight: g, kg, mg
• Volume: ml, l, cl
• Length: mm, cm, m
• Pieces: pcs (piece)

Conversion between units is automatic. If a product has weight in grams and the reference unit is kilogram, the plugin will calculate the value automatically.

Product variants

For variable products, the unit price can be set at two levels:

1. At the parent product level - value inherited by all variants
2. At the variant level - overrides parent product settings

For variants with different weights (e.g. 250 g and 500 g packages), set the unit price separately for each variant. The plugin will automatically update the displayed price when the customer changes the variant (AJAX).

Shortcode

Use the shortcode [polski_unit_price] to display the unit price anywhere.

Parameters

Parameter	Type	Default	Description
product_id	int	current	Product ID
before	string	""	Text before the price
after	string	""	Text after the price
wrapper	string	span	Wrapping HTML element

Usage examples

Basic usage on the product page:

[polski_unit_price]

With a custom product ID and text:

[polski_unit_price product_id="123" before="Price per kg: " after=" gross"]

In a PHP template:

echo do_shortcode('[polski_unit_price product_id="' . $product->get_id() . '"]');

Hook: polski/price/unit_price_html

This filter allows you to modify the unit price HTML before display.

Signature

apply_filters('polski/price/unit_price_html', string $html, float $unit_price, WC_Product $product, array $args): string

Parameters

Parameter	Type	Description
$html	string	Generated unit price HTML
$unit_price	float	Calculated unit price
$product	WC_Product	WooCommerce product object
$args	array	Array with keys: base_qty, base_unit, ref_qty, ref_unit

Example: adding a CSS class

add_filter('polski/price/unit_price_html', function (string $html, float $unit_price, WC_Product $product, array $args): string {
    $category_class = '';
    if (has_term('napoje', 'product_cat', $product->get_id())) {
        $category_class = ' polski-unit-price--beverage';
    }

    return sprintf(
        '<span class="polski-unit-price%s">%s/%s</span>',
        esc_attr($category_class),
        wc_price($unit_price),
        esc_html($args['ref_unit'])
    );
}, 10, 4);

Example: hiding unit price for selected categories

add_filter('polski/price/unit_price_html', function (string $html, float $unit_price, WC_Product $product): string {
    if (has_term('uslugi', 'product_cat', $product->get_id())) {
        return '';
    }

    return $html;
}, 10, 3);

CSV import

Unit prices can be imported using the standard WooCommerce importer. Add the following columns to the CSV file:

CSV column	Description
polski_unit_base_qty	Base quantity
polski_unit_base_unit	Base unit
polski_unit_ref_qty	Reference quantity
polski_unit_ref_unit	Reference unit

Example CSV row:

"Ground coffee 500g",29.99,500,g,1,kg

Common issues

Unit price does not display

Check that:

1. The unit price module is enabled in settings
2. The product has the base quantity and unit fields filled in
3. The theme supports the woocommerce_after_shop_loop_item_title hook (listing) and the woocommerce_single_product_summary hook (product page)

Incorrect conversion

Make sure the base unit and reference unit belong to the same category (e.g. both weight or both volume). The plugin does not convert between categories - you cannot convert grams to liters.

Related resources

• Report an issue

This page is for informational purposes only and does not constitute legal advice. Consult a lawyer before implementation. Polski for WooCommerce is open source software (GPLv2) provided without warranty.