UPS API - Product Weights?

I just put together a website using nopCommerce, and we are almost ready to go live, but have a few questions about shipping.

How does Nop Calculate the Shipping Sizes/Weights for the UPS API?

I know that you can enter the size and weight in the product info, but should it be by the size of the box the product has to be shipped in and the weight of the product and the shipping box together, or just the product itself?

What we don't understand is how is the shipping rate calculated if a customer orders multiple products that we will put in one box if we are entering in the product info the box size and weight for each product?

The UPS plugin config page offers three types of packing:
Packing type:
>Pack by dimensions
>Pack by one item per package
>Pack by volume

Pack by dimensions is IMHO not a very good algorithm, because it sums each set of dimensions (H, W, L) independently, and then divides each by a 'maximum package size' to determine (approximate) the # of packages.  It tends to overcharge if there are many items (quantity) in the cart.

Pack by one item per package is pretty obvious.  It can potentially overcharge because although shipping is generally weight based (although now the carriers are now always determining if dimensional weight applies), yet there is a base price for each package - i.e. many packages of total weight X is more expensive than 1 package of weight X.

Pack by volume uses a cubic root approximation.  It calculates the volume of each item (quantity), and approximates number of packages by taking the cubic root of packing volume (setting on config page) to get a normalized single length for each dimension (H,W,L).  In general, I think this is most accurate, unless you have light weight items with odd shapes (e.g. one very long side) that would always incur dimensional weight.

In any case, "packing" and its resultant rate is an approximation, and the ultimate set of manually packed boxes and rate paid could differ.   Unless you are using "Pack by one item per package", I would set up the product weight / dimensions with its actual packaging and not use the weight/dim of the box it might be packed in.  As I indicated before, weight is the most critical factor.  You can always add "Additional handling charge:" if you need to.

thanks for the great response, a few more questions though.....

To set it up for Pack by Volume do I enter the actual product/package size and weight for each of my products in the product info on nop?

Also under the Configure UPS Under "Packing Type" there is  "Packing Volume" and "Tracing", what value do I put in the Packing Volume, and what is tracing?

Yes, for Pack by Volume I'd recommend entering the actual product/package size and weight in the admin product info page.

RE: Packing Volume setting
I had a typo above and corrected it.  "cubic root of total volume"  should have read "cubic root of packing volume".
For the default 5184, the cubic root is 17 (integer), and thus your packing box has dimensions of 17 x 17 x 17.  You might want to adjust packing volume setting to suit your "typical" box size.

RE: tracing
Diagnostic messages will be written to the System log.  Be sure that this is NOT enabled in production. (Unless you are specifically troubleshooting something):
"UPS Get Shipping Options for customer {0}.  {1} item(s) in cart"
" Packing Type: "
" Package: LxHxW={0}x{1}x{2}; Weight={3}; Insured={4} {5}."
The API request XML
The API response XML

New York wrote:

For Packing by Volume, what unit should the volume be in? 5184 is cubic inches. Does it get converted to the stores specific units (to cubic meters when the store is configured as that), or should we enter the value in cubic meters or millimeters (ie, the dimensions unit configured for the store?)

Thanks

It used to be that dimensional weight (for Ground) was only triggered if the package is over 3 cubic feet, or 5,184 cubic inches.  But as of 2015 the carriers (FedEx, UPS) started using dimensional weight for all packages.  So, as per above I think you can just 'adjust packing volume setting to suit your "typical" box size'.

Just to clarify our question (and maybe answer it). We setup our store to use mm as the unit for product dimensions, but we weren't sure if the 5184 value (for the typical box size) in the component was supposed to be in the store's configured unit (or if it should always be in cubic inches).

Looking in the UPS plugin source, it converts all dimensions to inches, so the setting in the component should be your typical box size in cubic inches regardless of the dimension unit configured for the store.

How important is the box size when using volume?  We ship such a wide range of boxes, I am not sure what to put in.  Should I just go with the largest option?

The default volume is what used to be the when the carrier started applying dimensional weight.  I believe that carriers are using dim weight regardless now, so it's not so important.   In any case, the rate you get from the carrier is still only an approximation, since the packing you actually do is not necessarily going to match.   YOu should leave the default and do some tests.

I'm using the nop UPS plugin with the Nop 4.20.  When I test some products I could notice some differences between the plugin rates and the "UPS web --> Calculate Time and Cost" option value.
Here are my UPS plugin configurations.
        UPS Customer Classification = Retail Rates
         UPS Pickup Type  = Daily Pickup
         UPS Packaging Type  = Customer Supplied Package
          Additional handling charge  = 0.0000
         Packing type = Pack By Dimensions
          Pass dimensions  = enabled
Here are my product details.
          Product weight = 0.67lbs
          lenght =width = height = 1 in
Results I received from "UPS web site --> Calculate Time and Cost" service.
      Ground - $9.46
       UPS 2nd Day Air -$24.01
        UPS Next Day Air Saver - $50.98
Rates I received from my Nop UPS plugin
        Ground - $9.70
       UPS 2nd Day Air -$22.02
        UPS Next Day Air Saver - $47.49
Please help me to identify the reason for this rate difference.