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Multiple box sizes is a Pro feature. Upgrade to BoxBuilder Pro →
BoxBuilder Pro lets you offer multiple sizes for a single box product — for example, Small (6 items, 19.99),Medium(12items,19.99), Medium (12 items, 34.99), and Large (24 items, $59.99). The customer picks their size before building the box.

Setting Up Sizes

1

Enable BoxBuilder on a product

Edit your box product and go to the BoxBuilder tab.
2

Add sizes

In the Box Sizes section, add your sizes. Each size has:
  • Label: The name customers see (e.g., “Small”, “Medium”, “Large”)
  • Capacity: How many items this size holds
  • Price: The price for this size (used with fixed or hybrid pricing)

Size Display Settings

Configure size display in BoxBuilder → Settings → Cart under Box Sizes:

Size Display Style

StyleDescription
Cards (dropdown on mobile)Visual cards showing label, capacity, and price — automatically switches to dropdown on small screens (default)
Dropdown selectorA compact dropdown menu — useful when you have many size options
You can also set the Cards Per Row (2, 3, 4, or 5 — default is 3) to control how many size cards appear in a row.

Size Change Behavior

When a customer changes their size after already adding items to the box, you can control what happens:
BehaviorDescription
Keep items that fit, remove excessItems that still fit the new capacity are kept; excess items are removed (default)
Prevent size changeBlock size changes when items exceed the new capacity
Show warning and ask to confirmDisplay a confirmation dialog before changing

Example Configuration

SizeCapacityPrice
Small6 items$19.99
Medium12 items$34.99
Large24 items$59.99
Party Box48 items$99.99
Use sizes to create natural upsell opportunities. Show the per-item savings for larger sizes — “Small: 3.33/itemvsLarge:3.33/item vs Large: 2.50/item”.

How Sizes Work with Pricing

Pricing ModelSize Price Behavior
FixedEach size has its own fixed price
Per-ItemSize has no price — total is sum of items
HybridEach size has a base price + per-item prices