This guide is specifically for sellers using Automatic Shipping (USPS Ground Advantage only).

Automatic Shipping:

• Uses USPS Ground Advantage
• Packs items into your available parcel templates (box sizes)
• Tries to use the fewest boxes possible
• Calculates rates based on weight, dimensions, and destination

Think of it like Tetris — the system tries to fit everything into as few boxes as possible to keep shipping costs lower .

If shipping looks wrong, it’s almost always a box size or weight setup issue.

When to Use This Guide

Use this guide if:

• Shipping increases a lot when multiple items are added
• Items that should ship together are splitting into multiple charges
• Shipping looks higher than expected
• Customers see no shipping options at checkout
• You recently switched shipping methods

Why Does Shipping Increase So Much When Customers Add Multiple Items?

Automatic Shipping tries to fit items into the fewest boxes possible .

If items are splitting into multiple shipments, it usually means:

• You don’t have a box large enough for them to combine
• Parcel template dimensions are too small
• Ships alone is enabled on a product
• Weight is pushing the shipment into a higher tier

How Automatic Shipping Actually Combines Products

Here’s what the system does :

Step 1: Looks at Your Available Boxes

It checks:

• Default box sizes (XS, Small, Medium, Envelope)
• Any custom parcel templates you’ve created

Step 2: Tries to Fit Products Together

It attempts to pack items into the smallest number of boxes possible.

Step 3: Chooses the Option with the Fewest Boxes

Fewer boxes = usually lower USPS Ground Advantage cost.

If items don’t fit into a larger available box, they will ship separately.

My Items Should Ship Together - But They Aren’t

This is one of the most common issues with automatic shipping.

The Most Common Cause:

You don’t have a box large enough for multiple items.

According to the calculation guide :

If:

• Your product uses a 4" × 4" × 4" box

To ship 2 together, you need:

• 8" × 4" × 4" (one dimension doubled)

To ship 3 together, you need:

• 12" × 4" × 4" (one dimension tripled)

If that larger box doesn’t exist in your parcel templates, the system has no way to combine them.

How to Fix It

1. Go to your Parcel Templates
2. Look at the box size assigned to your product
3. Add a larger box where one dimension is 2× (or 3×) bigger
4. Test checkout with multiple items

That’s it.

The system will automatically use the larger box when possible .

Shipping Is Too Expensive for Multiple Items

If shipping feels too high:

Check 1: Are Items Being Split Into Too Many Boxes?

If yes:

• You likely don’t have appropriate larger box sizes
• Or dimensions are slightly too tight to combine

Fix:

• Add a larger parcel template
• Round dimensions realistically (but accurately)
• Remove unnecessary Ships Alone flags

Check 2: Are You Using “Ships Alone”?

Avoid using Ships Alone unless absolutely necessary (like for fragile or oversized items) .

If enabled:

• That product will always generate its own shipment and shipping cost
• Shipping rates will never combine

Check 3: Are Dimensions Too Large?

Overestimating box size can:

• Increase dimensional weight
• Increase USPS pricing tiers
• Force separate packaging

Better to measure actual packed size and round slightly up - not dramatically up .

Why Is Shipping Higher Than USPS Retail?

Remember:

Automatic Shipping uses USPS Ground Advantage only.

It does not offer:

• Media Mail
• Stamps pricing
• Priority
• First-Class letter pricing

If you normally ship small items with stamps, automatic shipping may appear more expensive.

Also check:

• Weight accuracy (1 lb instead of 1 oz causes major jumps)
• Oversized dimensions triggering dimensional pricing

Why Are There No Shipping Options at Checkout?

If customers see:

• We don’t ship to this location
• No shipping options at checkout
• Checkout errors

Check:

1. Shipping Regions

Go to:

Shop Settings → Shipping

Confirm:

• The destination country/state is included
• You didn’t accidentally remove a region

If the customer’s location isn’t covered, USPS rates cannot generate.

2. Product Shipping Setup

Each product must have:

• A weight entered
• A parcel template assigned
• Valid dimensions

Missing data prevents rate calculation.

How can I do a local pickup option with automatic shipping enabled?

To offer free shipping like local pickup with automatic shipping enabled, you’ll need to create a discount for free shipping and let your customers know they’ll need to apply that discount code at checkout if they want to do local pickup. More on creating discounts here.

What Happens If I Switch Between Manual and Automatic?

Manual and Automatic shipping are mutually exclusive.

When Automatic Shipping is active:

• Shipping profiles are hidden
• Manual rate logic is disabled
• Parcel templates control packaging behavior

If things look broken after switching:

1. Confirm Automatic Shipping is enabled
2. Review product weights
3. Review parcel templates
4. Re-test checkout from scratch

Switching requires reconfiguration.

Quick Automatic Shipping Health Checklist

Before contacting support, confirm:

• Each product has accurate weight
• Each product has the correct box assigned
• You have larger boxes available for multi-item orders
• Ships Alone is only used when required
• Dimensions are realistic (not oversized)
• Shipping regions include your customers
• You tested checkout with 1, 2, and 3 items

The Most Important Thing to Remember

You don’t need to understand the math.

Just remember :

• Give each product its correct box size
• Add larger boxes for multiple items
• Fewer boxes = cheaper shipping

The system handles the rest.

Still Having Trouble?

If items still aren’t combining correctly, contact support and include:

• Screenshot of checkout
• Products in cart
• Shipping destination used
• Product weight
• Assigned parcel template
• List of available box sizes

We’ll review your box logic and help you optimize for fewer boxes and better USPS Ground Advantage rates.