Tare weight, sometimes called unladen weight, is the weight of an empty vehicle or container. By subtracting it from the gross weight (ladenweight), the weight of the goods carried (the net weight) may be determined.
Tare weight – Wikipedia, the free encyclopedia en.wikipedia.org/wiki/Tare_weight
I can only speak from the point of view of an American. The USPS (United Postal Service) uses Imperial and US customary measurement system and most of the tare weights I’ve dealt with were under 1 lbs. If you use the formula of 1/16 x the number of ounces your box and packaging weigh, you have now found your calculated tare weight for the purposes of estimating better shipping in your e-commerce shopping cart.
You should also remember that each package has its own tare weight or total package weight and your supplier should have that information for you. You would then use that information while creating your product entry excluding any tare weight which most often would be configured in your shipping modules.