Magendoo Base Price — Magento 2 Module

Displays a per-unit reference price (Grundpreis) next to every product's selling price across product pages, category listings, search results, and the shopping cart.

A customer buying a 300 g shampoo at €4.99 also sees "Base price: €16.63 / 1 kilogram", enabling direct price comparison across different pack sizes and brands.

Legal background

Displaying a unit reference price is legally required in several jurisdictions:

• Germany — Preisangabenverordnung (PAngV §4)
• EU member states — Price Indication Directive 98/6/EC, updated by Directive 2019/2161 (Omnibus)

The obligation applies to products sold by weight, volume, length, area, or piece count that are offered in different pack sizes. Consult your legal adviser to determine your specific requirements.

Requirements

Installation

Via Composer (recommended)

composer require magendoo/module-base-price
bin/magento setup:upgrade
bin/magento setup:di:compile
bin/magento cache:flush

Manual

mkdir -p app/code/Magendoo/BasePrice
# Copy all module files into that directory
bin/magento setup:upgrade
bin/magento setup:di:compile
bin/magento cache:flush

setup:upgrade creates the magendoo_baseprice_unit table, adds four EAV product attributes, and seeds nine SI measurement units.

Configuration

Navigate to Stores → Configuration → Magendoo Extensions → Base Price.

General

Product Page

Category & Search

Cart

Template variables

All display templates accept the following placeholders:

Unknown placeholders are left intact, so you can safely mix in static text.

Formula

base_price = (selling_price ÷ product_amount) × (reference_amount × rate)

Where rate is the conversion factor from the product unit to the reference unit (e.g. 1 000 for gram → kilogram).

Examples:

The result is rounded to 4 decimal places before formatting.

Reference amount override

A product can override the unit's default reference amount. Set Reference Amount to 0.1 on a gram-unit product to show the price per 100 g instead of per kilogram:

(4.99 ÷ 300) × (0.1 × 1 000) = €1.66 / 100 g

Unit management

Navigate to Catalog → Base Price Units in the admin panel.

Nine SI units are pre-installed:

Adding a custom unit

Click Add New Unit and fill in:

Configuring products

Admin UI

Open any product in the admin and locate the Base Price panel (below the standard price fields):

REST API — set a product's base price

TOKEN=$(curl -s -X POST https://your-store.com/rest/V1/integration/admin/token \
  -H 'Content-Type: application/json' \
  -d '{"username":"admin","password":"your-password"}' | tr -d '"')

# Set base price (300 g, gram unit = ID 1)
curl -X PUT https://your-store.com/rest/V1/baseprice/products/24-MB01 \
  -H "Authorization: Bearer $TOKEN" \
  -H 'Content-Type: application/json' \
  -d '{
    "productBasePrice": {
      "sku": "24-MB01",
      "product_amount": 300,
      "unit_id": 1
    }
  }'

# Enable it on the product
curl -X PUT https://your-store.com/rest/V1/products/24-MB01 \
  -H "Authorization: Bearer $TOKEN" \
  -H 'Content-Type: application/json' \
  -d '{
    "product": {
      "sku": "24-MB01",
      "custom_attributes": [
        {"attribute_code": "baseprice_is_enabled", "value": "1"}
      ]
    }
  }'

REST API reference

Units (admin token required)

Create a unit:

curl -X POST https://your-store.com/rest/V1/baseprice/units \
  -H "Authorization: Bearer $TOKEN" \
  -H 'Content-Type: application/json' \
  -d '{
    "unit": {
      "name": "fluid ounce",
      "reference_unit_label": "litre",
      "rate": 33.814,
      "reference_amount": 1,
      "position": 100,
      "active": true
    }
  }'

Note: The active flag is sent as active, not is_active. Magento's serialiser strips the is prefix from getter method names when building the response body.

Product base price (admin token required)

Calculator (anonymous)

GET /V1/baseprice/calculate?price=4.99&productAmount=300&unitId=1

Returns the raw base price as a float. Optional parameter: referenceAmountOverride.

curl 'https://your-store.com/rest/V1/baseprice/calculate?price=4.99&productAmount=300&unitId=1'
# → 16.6333

Architecture notes

• EAV attributes — Four product attributes (baseprice_is_enabled, baseprice_product_amount, baseprice_unit_id, baseprice_reference_amount) are registered with used_in_product_listing = true so they load in category and search collections.
• Listing injection — A plugin on Magento\Catalog\Block\Product\AbstractProduct::getProductDetailsHtml() appends the base price HTML to every product card, covering all product types without type-specific renderer registration.
• Cart injection — The cart block is a child of Magento's additional.product.info block. The cart item template iterates through its children and calls setItem() + toHtml() on each.
• Product page — A standard Template block is added via catalog_product_view.xml and the product block is retrieved directly from layout.
• Template rendering — Model/TemplateRenderer does a plain str_replace over {{variable}} placeholders. HTML escaping is the caller's responsibility; priceCurrency->format() handles currency formatting.

Releases and Packagist

Creating a release

Tag a version and push — the Release workflow runs tests then creates a GitHub release automatically:

git tag v1.2.0
git push origin v1.2.0

Version numbers follow Semantic Versioning. Update CHANGELOG.md and composer.json ("version") before tagging.

Publishing to Packagist

1. Go to packagist.org/packages/submit and enter:

   https://github.com/magendooro/module-base-price
   

2. After submission, enable auto-update so Packagist picks up new tags automatically:

   • In the Packagist package settings, copy the webhook URL
   • In the GitHub repository: Settings → Webhooks → Add webhook → paste the URL
   • Content type: application/json, events: Just the push event

   Alternatively, connect your GitHub account to Packagist (Settings → Profile → GitHub) which handles webhooks automatically.

GitHub Secrets required for CI

The workflows install Magento packages from repo.magento.com, which requires Marketplace credentials. Add these to the repository as Actions secrets (Settings → Secrets and variables → Actions):

Without these secrets the CI runs will fail at the composer install step.

Running tests

PHPUnit (unit tests)

# From the Magento root
vendor/bin/phpunit --filter Magendoo\\BasePrice app/code/Magendoo/BasePrice/Test/Unit

Playwright (functional tests)

The functional test suite lives in dev/tests/functional/playwright/tests/baseprice/ and covers:

• baseprice-calculate-combinations.spec.js — All nine seed units, referenceAmountOverride, edge cases, formula consistency (45 tests, no products or admin setup needed — hits the anonymous /V1/baseprice/calculate endpoint directly)
• baseprice-product-display.spec.js — Product detail page, category listing, cart page, disabled state (22 tests, sets up three sample products in beforeAll and restores them in afterAll)

cd dev/tests/functional/playwright
npx playwright test tests/baseprice/

Uninstall

bin/magento module:uninstall Magendoo_BasePrice
bin/magento setup:upgrade
bin/magento cache:flush

This removes the magendoo_baseprice_unit table and the four EAV product attributes.

License

MIT — see LICENSE for details.

Changelog

All notable changes to this project will be documented in this file.

The format follows Keep a Changelog.
This project adheres to Semantic Versioning.

Unreleased

1.0.0 - 2026-04-13

Added

• Base price calculation and display on product detail pages, category listing pages, search result pages, and the shopping cart
• Formula: (selling_price ÷ product_amount) × (reference_amount × rate), rounded to 4 decimal places
• Nine pre-installed SI measurement units: gram, milligram, kilogram, millilitre, centilitre, litre, centimetre, metre, piece
• Configurable display templates with six {{variable}} placeholders: unit_price, reference_amount, reference_unit, measure_unit, product_amount, product_price
• Admin unit management grid at Catalog → Base Price Units (create, edit, delete, mass-enable/disable)
• Per-product enable/disable toggle and optional reference amount override (e.g. show per 100 g instead of per kg)
• REST API: unit CRUD (/V1/baseprice/units), product base price read/write/delete (/V1/baseprice/products/:sku), and an anonymous calculator endpoint (/V1/baseprice/calculate)
• EAV attributes baseprice_is_enabled, baseprice_product_amount, baseprice_unit_id, baseprice_reference_amount with used_in_product_listing = true for efficient collection loading
• 32 PHPUnit unit tests covering every calculation combination, reference amount override, edge cases, template rendering, and formatting
• PHPStan level 2 clean