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# Product Group Rate Behaviour

# Product Group Rate Behaviour

When a customer's cart contains products from multiple product groups, you can control how shipping rates are calculated and displayed at checkout.  Note that this feature is only available when using app-based product groups.

### Configuration

Navigate to **Regions > Edit Region > Product Group Rate Behaviour** to select your preferred calculation method.

### Available Options

### Sum (Default)

**What it does:** Adds together the lowest rate from each product group, plus the general rate if applicable.

**Best for:** Most merchants - ensures all product groups are accounted for in the shipping cost.

**Example:**
* General rate: "Normal Shipping" - $3
* Product Group A rate: "Normal Shipping" - $5
* Product Group B rate: "Normal Shipping" - $8

**Customer sees:** One rate option called "Normal Shipping" for **$16**


### Highest

**What it does:** Returns only the single highest rate across all product groups.

**Best for:** When you want to charge the maximum shipping cost from any group, regardless of title.

**Example:**
* General rate: "Normal Shipping" - $3
* Product Group A rate: "Fast Shipping" - $7
* Product Group B rate: "Express Shipping" - $12

**Customer sees:** One rate option called "Express Shipping" for **$12**


### Lowest

**What it does:** Returns only the single lowest rate across all product groups.

**Best for:** Offering the most competitive shipping price when multiple groups are involved.

**Example:**
* General rate: "Normal Shipping" - $3
* Product Group A rate: "Fast Shipping" - $7
* Product Group B rate: "Express Shipping" - $12

**Customer sees:** One rate option called "Normal Shipping" for **$3**


### Highest Unique

**What it does:** For each shipping option that appears across all product groups, returns the highest price for that option.

**Best for:** When you want to offer multiple shipping speeds but charge the highest price for each speed.

**Example:**
* Product Group A rates: "Normal Shipping" ($5), "Fast Shipping" ($7)
* Product Group B rates: "Normal Shipping" ($8), "Fast Shipping" ($12)
* General rates: "Normal Shipping" ($3), "Fast Shipping" ($5)

**Customer sees:** Two rate options:
* "Normal Shipping" for **$8*** (highest of $3, $5, $8*)
* "Fast Shipping" for **$12** *(highest of $5, $7, $12)*


### Lowest Unique

**What it does:** For each shipping option that appears across all product groups, returns the lowest price for that option.

**Best for:** When you want to offer multiple shipping speeds at the most competitive price for each speed.

**Example:**
* Product Group A rates: "Normal Shipping" (5), "Fast Shipping" (7)
* Product Group B rates: "Normal Shipping" (8), "Fast Shipping" (12)
* General rates: "Normal Shipping" (3), "Fast Shipping" (5)

**Customer sees:** Two rate options:
* "Normal Shipping" for **$3** *(lowest of $3, $5, $8)*
* "Fast Shipping" for **$5** *(lowest of $5, $7, $12)*


### Important Notes

###### When Rate Titles Don't Match

For **Highest Unique** and **Lowest Unique** to work, you need shipping options with the **same title** across all your product groups.

If rate titles don't match (e.g., Product Group A has "Standard" but Product Group B has "Regular"), the system will automatically fall back to the **Sum** behaviour and return a single "Shipping" rate.

###### Backwards Compatibility

Existing regions will continue using **Sum** behaviour unless you actively change the setting. This ensures no disruption to your current shipping configuration.

###### Product Groups Feature Required

This setting only applies when the **Product Groups** feature is enabled for your store. Without product groups, this setting has no effect.


### Common Use Cases

| Scenario | Recommended Option |
| ---- |
| Default setup - need to account for all products | **Sum** |
| Bulky items that dominate shipping cost | **Highest** |
| Want to offer cheapest option possible | **Lowest** |
| Multiple rate services, charge highest for each | **Highest Unique** |
| Multiple rate services, offer best price for each | **Lowest Unique** |


### Need Help?

If you're unsure which option is right for your business, contact our support team and we'll help you configure the best setup for your needs.