Hi - I have a question regarding shipping rates. I ship in the USA only and use USPS Flat Rate Boxes listed under Settings - Shipping and Delivery - Saved Packages.
My product is granola, 6 bags minimum, weight 4.62 lbs. A purchase of 1 unit (6 bags of granola) fits in a USPS Flat Rate Box A. However, a purchase of 2 units (12 bags of granola) fits in a USPS Medium Flat Rate Box. USPS Flat Rate boxes are not weight based calculated. Rates are based on the size of the box only. I need shipping to default to Flat Rate Box A for 1 unit (6 bags) and default to Medium Flat Rate Box for 2 units (12 bags). How do I do this when weight is not the basis for shipping rate, only box size? twinforksfarm.com
Shopify only offers one box size to be sent off for live rate calculations, regardless of the size of the actual order. Since you can only set up one default package in Shopify, the only way to handle this is manually choosing the correct box based on the order you receive.
If you want ti automate the process of selecting the right box based on your order, you would need a shipping app if you are looking to charge based on the dimensional weight of the package. The benefit here is that you know you are charging the right price for shipping, so whenever you get an order, you know it's profitable.
I would suggest you try the Multi Carrier Shipping Label app, that helps you handle this with ease. With the box packing method in the app, you can set up different packages for your products based on the weight & dimensions. So, whenever your customer places an order, the app automatically chooses the right box and calculates the rates accordingly. Also, with the app, you can print labels, and also automate the tracking process. You can try the app with a 14-day free trial and contact the support if you require any assistance.