Package Size per Product (New feature)?

Store Design

Topic summary

Shopify’s new per-product package size feature allows merchants to assign specific dimensions and weights to individual products. However, the implementation has significant limitations:

Key Finding:

  • Custom package sizes only apply to single-item orders
  • For multi-item orders, Shopify defaults to the global default package setting, regardless of individual product configurations
  • The system does NOT automatically select the largest package or combine dimensions intelligently

Practical Impact:

  • An oversized item shipped alone uses its correct custom package (including dimensional weight)
  • The same oversized item combined with smaller items reverts to the default package, potentially undercharging shipping costs
  • Merchants cannot rely on this feature for accurate multi-item shipping calculations

Workarounds Suggested:

  1. Manually adjust package sizes during fulfillment
  2. Set a conservative default package that covers most scenarios
  3. Use third-party shipping apps (Boxify, PluginHive, Shippo, Starshipit) for automated box selection based on cart contents
  4. Continue adjusting product weights as a workaround

The feature appears designed primarily for single-SKU orders rather than mixed-cart scenarios.

Summarized with AI on October 25. AI used: claude-sonnet-4-5-20250929.
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Now that we can set individual product package size, what is the logic when it comes to smaller and larger packages? Will it default to the worst package size?

I tried to ask AI help and in general I couldn’t come up with much information on this feature.

Thanks

1 Like
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I don’t see the edit anymore in the community, but if you hover it says this is what is used for the single item calculation.

Unfortunately it looks like I will have to still bump up the weights instead as most orders contain multiple items.

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Hi @chrisngrod1 ,

Yes—at checkout, Shopify effectively defaults to whichever package you’ve set as the overall default, regardless of your per-product package settings. It does not automatically apply the “worst” (i.e., the largest), but rather the one default you’ve designated in your shipping settings. Even if an item is small, checkout still calculates shipping using the default box.

What You Can Do Next

  1. Select a reasonable default package that best matches the majority of your orders—this helps minimize mismatch.
  2. For orders with specific shipping needs, change the package manually during fulfillment.
  3. Explore shipping apps like Boxify, PluginHive, Shippo, Starshipit, etc., which can automate box selection and shipping based on cart contents and product dimensions.
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Hello @chrisngrod1

The new per-product package size feature in Shopify lets you define dimensions/weight for individual products instead of using one global package profile. When a customer checks out with multiple items, Shopify’s shipping engine evaluates the combined order and chooses a package configuration that can contain them all.

In practice this means:

  • If you have a small product, Shopify will use its defined package when it ships alone.
  • If you combine it with a larger product, Shopify defaults to the package that can actually fit everything (i.e. the larger one).
  • It won’t “double up” packaging unless you set multiple package options or carrier rules that allow splitting.

So yes — when mixed, it tends to “default” to the larger package size to ensure items fit, but you can override by creating additional package rules or carrier boxes if needed.

Note: If you’d like, I can help set up optimized package profiles and shipping rules so you don’t always end up with the “worst-case” size. Feel free to contact me at devcodersp@gmail.com

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I just tested this. Our store has a mix of oversized items (items whose dimensional weight is greater then the package weight) and small items. Results when non-global default package size was added to an oversized item:

When Oversized Item is shipped alone: Correct shipping charge is applied for item (including dimensional weight).

When Oversized Item is shipped with a small item: Default Package size (non-oversized package) is used. Since Default package size is non-oversized, this results in a much lower shipping charge.

In conclusion, Shopify does NOT pick the largest package size when it sees multiple packages. Rather, it uses the Default Package size. Shopify’s info comment of “Used for single-item orders containing this product” is correct - custom package sizing on the item level is ONLY used for orders containing ONLY that item.