> For the complete documentation index, see [llms.txt](https://responsive-media.gitbook.io/advanced-free-shipping/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://responsive-media.gitbook.io/advanced-free-shipping/conditions-cart-and-order/cart-weight.md).

# Cart Weight

## Overview

The **Cart Weight** condition applies discounts based on the total weight of all items in the customer's cart. This is useful when shipping costs correlate with weight.

## How Weight is Calculated

```
Cart Weight = Sum of (item weight × quantity) for all line items
```

**Example cart**:

* Product A: 2 lbs × 2 qty = 4 lbs
* Product B: 1.5 lbs × 1 qty = 1.5 lbs
* Product C: 0.5 lbs × 3 qty = 1.5 lbs

**Cart Weight**: 4 + 1.5 + 1.5 = **7 lbs**

{% hint style="info" %}
Weight is calculated using the weight values set on your product variants in Shopify.
{% endhint %}

## Available Weight Units

Choose the unit that matches your store's configuration:

**Grams (g)** - Metric system, fine precision

**Kilograms (kg)** - Metric system, standard weight

**Ounces (oz)** - Imperial system, fine precision

**Pounds (lb)** - Imperial system, standard weight

{% hint style="warning" %}
Make sure the unit you select matches how your products are weighted in Shopify. Mixing units will cause incorrect calculations.
{% endhint %}

## Available Operators

All numeric operators are available:

* **Is greater than**
* **Is less than**
* **Is equal to**
* **Is at least** - Most common
* **Is at most**

## Common Use Cases

### Heavy Order Free Shipping

**Free shipping for orders over 20 lbs**

**Configuration**:

* Condition: Cart weight **is at least** 20 **pounds**
* Target: All shipping rates → Free

**Use case**: Absorb shipping costs on heavy orders where shipping is already expensive.

### Lightweight Order Discount

**Flat $3 shipping for orders under 5 lbs**

**Configuration**:

* Condition: Cart weight **is at most** 5 **pounds**
* Target: All shipping rates → $3 flat rate

**Use case**: Offer affordable shipping on lightweight items that are cheap to ship.

### Weight-Based Tiers

**Graduated discounts by weight**

Create multiple discounts:

1. **5-10 lbs: 25% off**
   * Condition: Cart weight **is at least** 5 **pounds**
2. **10-20 lbs: 50% off**
   * Condition: Cart weight **is at least** 10 **pounds**
3. **20+ lbs: Free**
   * Condition: Cart weight **is at least** 20 **pounds**

### International Weight Limits

**Different thresholds by region**

* Rule Group 1 (US):
  * Condition 1: Country **is** US
  * Condition 2: Cart weight **is at least** 10 **pounds**
* Rule Group 2 (International):
  * Condition 1: Country **is not** US
  * Condition 2: Cart weight **is at least** 5 **pounds**

Lower threshold for international to offset higher shipping costs.

## Combining with Other Conditions

### Weight + Value

**Free shipping for heavy OR expensive orders**

* Rule Group 1:
  * Condition: Cart weight **is at least** 20 **pounds**
* Rule Group 2:
  * Condition: Cart total **is at least** $100

Either heavy orders OR high-value orders get free shipping.

### Weight + Location

**Weight-based shipping for specific regions**

* Condition 1: Country **is** US
* Condition 2: Cart weight **is at most** 10 **pounds**
* Discount: $5 flat rate

Offer flat rate shipping for lightweight US orders.

### Weight + Product Type

**Free shipping on heavy furniture**

* Condition 1: Collection **contains** "Furniture"
* Condition 2: Cart weight **is at least** 50 **pounds**

Absorb shipping on large furniture orders.

## Unit Conversion Reference

{% tabs %}
{% tab title="Metric to Imperial" %}
**Grams to Ounces**: 1 g = 0.035 oz **Kilograms to Pounds**: 1 kg = 2.205 lbs

**Common conversions**:

* 500 g = 17.6 oz (≈ 1.1 lbs)
* 1 kg = 35.3 oz (≈ 2.2 lbs)
* 5 kg = 176.4 oz (≈ 11 lbs)
* 10 kg = 352.7 oz (≈ 22 lbs)
  {% endtab %}

{% tab title="Imperial to Metric" %}
**Ounces to Grams**: 1 oz = 28.35 g **Pounds to Kilograms**: 1 lb = 0.454 kg

**Common conversions**:

* 1 lb = 16 oz (≈ 454 g)
* 5 lbs = 80 oz (≈ 2.27 kg)
* 10 lbs = 160 oz (≈ 4.54 kg)
* 20 lbs = 320 oz (≈ 9.07 kg)
  {% endtab %}

{% tab title="Within Metric" %}
**Grams to Kilograms**: 1 kg = 1000 g

**Common values**:

* 500 g = 0.5 kg
* 1000 g = 1 kg
* 2500 g = 2.5 kg
* 5000 g = 5 kg
  {% endtab %}

{% tab title="Within Imperial" %}
**Ounces to Pounds**: 1 lb = 16 oz

**Common values**:

* 8 oz = 0.5 lbs
* 16 oz = 1 lb
* 32 oz = 2 lbs
* 160 oz = 10 lbs
  {% endtab %}
  {% endtabs %}

## Best Practices

{% hint style="info" %}
**Match your product weights.** Check how your products are weighted in Shopify and use the same unit for consistency.
{% endhint %}

{% hint style="info" %}
**Consider shipping carrier limits.** Many carriers have weight-based pricing tiers. Align your thresholds with these tiers.
{% endhint %}

{% hint style="info" %}
**Combine with value thresholds.** Weight alone might not reflect order value. Use OR logic with cart total for flexibility.
{% endhint %}

{% hint style="info" %}
**Test with real products.** Add actual products to a test cart and verify the weight calculation matches your expectations.
{% endhint %}

{% hint style="warning" %}
**Products without weight won't count.** If your products don't have weight values set in Shopify, they'll be treated as 0 weight. Make sure all products have accurate weights.
{% endhint %}

## When to Use Weight vs Other Conditions

| Use Weight When                      | Use Value Instead When               |
| ------------------------------------ | ------------------------------------ |
| Shipping costs correlate with weight | Products have similar weights        |
| Selling heavy/bulky items            | Selling digital or lightweight items |
| Carrier charges by weight            | Shipping is flat rate                |
| International shipping               | Domestic shipping only               |

## Examples by Product Type

{% tabs %}
{% tab title="Books & Media" %}
**Scenario**: Bookstore with heavy orders

**Configuration**:

* Condition: Cart weight **is at least** 5 **pounds**
* Discount: Free shipping

**Why**: Books are heavy. 5 lbs ≈ 3-5 books, encouraging multi-book purchases.
{% endtab %}

{% tab title="Furniture" %}
**Scenario**: Furniture store with freight shipping

**Configuration**:

* Condition: Cart weight **is at least** 100 **pounds**
* Discount: $50 off shipping

**Why**: Heavy furniture has expensive shipping. Partial subsidy on large orders.
{% endtab %}

{% tab title="Apparel" %}
**Scenario**: Clothing store with lightweight items

**Configuration**:

* Condition: Cart weight **is at most** 2 **pounds**
* Discount: $3 flat rate

**Why**: Clothes are light. Offer cheap shipping on small orders (1-3 items).
{% endtab %}

{% tab title="Supplements" %}
**Scenario**: Vitamin/supplement store

**Configuration**:

* Condition: Cart weight **is at least** 2 **pounds**
* Discount: Free shipping

**Why**: Bottles are consistent weight. 2 lbs ≈ 3-4 bottles, encouraging bundles.
{% endtab %}
{% endtabs %}

## Troubleshooting

<details>

<summary>Weight calculation seems wrong</summary>

* Check product weights in Shopify admin
* Verify you're using the correct unit (lbs vs kg)
* Ensure all products have weight values set
* Test with a single product to verify calculation

</details>

<details>

<summary>Discount not applying</summary>

* Confirm cart weight meets the threshold
* Check if products have weight values in Shopify
* Verify the unit matches your product weights
* Test in Test Mode with known weights

</details>

<details>

<summary>Some products not counting</summary>

* Products without weight values are treated as 0 weight
* Go to Products in Shopify admin and add weights
* Digital products typically have no weight (this is expected)

</details>

## Related Conditions

* [**Cart Quantity**](/advanced-free-shipping/conditions-cart-and-order/cart-quantity.md) - Base discounts on number of items
* [**Cart Total**](/advanced-free-shipping/conditions-cart-and-order/cart-total.md) - Base discounts on cart value
* [**Shipping Country**](/advanced-free-shipping/conditions-location/shipping-country.md) - Combine with location for regional weight rules
* **Collection in Cart** - Weight-based discounts for specific collections


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