Package weight or content weight: keep packaging out of the unit calculation
By Erik Nilsen · Kroni2 min read
When your child compares price per quantity, that quantity must describe what will actually be used. A full package's weight may include its packaging. Find the content amount and compare the same kind of quantity for both offers.
Subtract packaging in this exercise
In a hypothetical example, a pack of modelling material A weighs 500 grams altogether, including 50 grams of packaging. It costs 45 units. B contains 400 grams of material excluding packaging and costs 40. The arbitrary figures are invented, with equally suitable materials assumed.
A contains 500 − 50 = 450 grams of usable material. Price per 100 grams is 45 / 450 × 100 = 10 units. B is 40 / 400 × 100 = 10. Their prices per content gram are identical.
Using A's full weight of 500 instead gives 45 / 500 × 100 = 9. A appears incorrectly cheaper because packaging counts as material. Do not use package weight when B already uses content alone.
Keep quantity and payment visible
A practical snag is “500 grams” looking bigger than “400” without reading what either describes. Label “whole package” and “material alone”, then find content before dividing.
If your child needs only 350 grams, either pack meets the need. B requires 40 paid now and A requires 45. Identical price per content gram does not mean identical cash payment or a need for the larger pack.
For an actual purchase, use stated contents or a confirmed measurement rather than guessing packaging weight. This exercise knows the 50 grams, while an unfamiliar pack needs more information.
Ask your family: “Does this quantity describe the material we need or its entire package?”
Carry the calculation into your family agreement
Kroni can keep track of your child's virtual balance. The app does not transfer money, so any actual purchase is paid for outside it. Agree on what you will record, then check the amount with your child afterwards. Do not deduct a possible cost as though the purchase had already happened. Read about allowance in Kroni.
