Product Based Shipping Logic for WooCommerce

Product Based Shipping Logic for WooCommerce is a small, secure WooCommerce plugin that lets store owners increase shipping cost site-wide based on the total number of products in the cart.

It is useful when you already have many WooCommerce shipping zones and do not want to manually edit every zone formula. The plugin keeps your existing shipping-zone prices as the base cost, then adjusts the final shipping rate during WooCommerce's server-side shipping calculation.

Author: Toxima

Contact: officialdevtosin@gmail.com

What The Plugin Does

• Adds an admin settings page at WooCommerce > Product Shipping Logic.
• Applies one site-wide shipping adjustment rule across your WooCommerce store.
• Uses your existing WooCommerce shipping-zone cost as the base shipping amount.
• Supports multiplication-based shipping increases.
• Supports percentage-based shipping increases.
• Applies to Flat rate shipping by default.
• Can optionally apply to all paid shipping methods.
• Never increases Free shipping.
• Never increases Local pickup.
• Supports an optional maximum shipping cap.
• Recalculates shipping server-side when WooCommerce calculates cart and checkout totals.
• Clears WooCommerce shipping cache when plugin settings change.

Example Use Case

You have many shipping zones:

• Lagos flat rate: 2000
• Abuja flat rate: 3500
• Port Harcourt flat rate: 4000

Without this plugin, you may need to edit each zone manually.

With this plugin, you leave those base prices alone. If a customer increases product quantity, the plugin adjusts the final shipping cost automatically.

Example with a base shipping fee of 2000:

Adjustment Modes

Multiplication Mode

This mode multiplies the base shipping fee by the cart quantity and by your configured multiplier value.

Formula:

base shipping x cart quantity x multiplier

Recommended setting for normal per-product shipping:

Multiplier per item: 1

Example:

Base shipping: 20
Quantity: 3
Multiplier: 1
Final shipping: 60

Percentage Mode

This mode increases the base shipping fee by a percentage for each extra item after the first item.

Formula:

base shipping + percentage increase for each extra item

If the percentage is 100, the result is the same as normal quantity multiplication.

Example:

Base shipping: 20
Quantity: 3
Percentage per extra item: 100
Final shipping: 60

Another example:

Base shipping: 1000
Quantity: 3
Percentage per extra item: 50
Final shipping: 2000

That means:

• First item keeps the base shipping: 1000
• Second item adds 50%: 500
• Third item adds 50%: 500
• Final shipping: 2000

Installation From WordPress Admin

1. Download product-based-shipping-logic.zip.
2. In WordPress admin, go to Plugins > Add New.
3. Click Upload Plugin.
4. Upload product-based-shipping-logic.zip.
5. Click Install Now.
6. Click Activate Plugin.
7. Go to WooCommerce > Product Shipping Logic.
8. Configure the shipping adjustment.
9. Save the settings.

Manual Installation

1. Upload the plugin files to:

wp-content/plugins/product-based-shipping-logic

2. Activate Product Based Shipping Logic for WooCommerce from the WordPress plugins page.
3. Go to WooCommerce > Product Shipping Logic.
4. Configure and save your settings.

Recommended Settings

For your original use case, use:

Enable adjustment: Enabled
Adjustment mode: Multiply base shipping by cart quantity
Multiplier per item: 1
Shipping methods affected: Flat rate only
Start adjustment at quantity: 2
Optional maximum shipping charge: leave empty

This gives:

20 x 1 product = 20
20 x 2 products = 40
20 x 3 products = 60

Settings Explained

Enable Adjustment

Turns the plugin logic on or off without deactivating the plugin.

Adjustment Mode

Choose how shipping should increase:

• Multiply base shipping by cart quantity
• Increase base shipping by percentage per extra item

Multiplier Per Item

Used only in multiplication mode.

Set this to 1 if every product should add one full shipping fee.

Percentage Per Extra Item

Used only in percentage mode.

Set this to 100 if every extra product should add another full shipping fee.

Set this to 50 if every extra product should add half of the base shipping fee.

Shipping Methods Affected

Recommended:

Flat rate only

This keeps the plugin focused on WooCommerce flat-rate shipping zones.

Advanced option:

All paid shipping methods

This can affect other paid shipping methods. Use it carefully and test before using it on a live store.

Start Adjustment At Quantity

Default:

2

This means quantity 1 keeps the original shipping price, and the plugin starts increasing shipping when the cart has 2 or more items.

Optional Maximum Shipping Charge

Leave empty for no maximum.

If you set a value, the plugin will not allow adjusted shipping to go above that amount.

What It Does Not Do

• It does not replace WooCommerce shipping zones.
• It does not create new shipping zones.
• It does not change product prices.
• It does not change tax settings.
• It does not increase free shipping.
• It does not increase local pickup.
• It does not rely on checkout JavaScript for security.

Security

The plugin is designed to keep shipping calculation secure and server-side.

• Admin settings are saved through the WordPress Settings API.
• The settings page requires the manage_woocommerce capability.
• Admin inputs are sanitized before storage.
• Admin output is escaped before display.
• Shipping calculation runs through WooCommerce's server-side woocommerce_package_rates filter.
• The plugin does not trust customer-side checkout input for final shipping totals.
• Structured errors use WooCommerce's centralized logger.

Caching

The plugin does not create a separate long-lived cache.

It relies on WooCommerce's shipping-rate caching and clears the WooCommerce shipping cache version when plugin settings are updated.

Testing Checklist

Before using this plugin on a live store:

1. Test on a local or staging WordPress site.
2. Install and activate WooCommerce.
3. Create at least one test product.
4. Create one shipping zone with a flat-rate cost, for example 20.
5. Activate this plugin.
6. Go to WooCommerce > Product Shipping Logic.
7. Enable multiplication mode with multiplier 1.
8. Add one product to cart and confirm shipping is 20.
9. Increase quantity to 2 and confirm shipping is 40.
10. Increase quantity to 3 and confirm shipping is 60.
11. Test free shipping and local pickup if your store uses them.
12. Test checkout using your normal payment method in test mode.

Requirements

• WordPress 6.0 or newer
• PHP 7.4 or newer
• WooCommerce 7.0 or newer

License

GPL v2 or later.