Is the weight of the packaging included in the weight of the sold item, or is it added to the required weight, knowing that it is customary to purchase coffee by the kilogram, including the packaging?

Honesty and clarity in selling are obligations and a source of blessing, while lying and deception are forbidden and erase blessing. Short-changing in measure is deception and fraud. The consideration between the contracting parties must be known and complete. If the contract is for a kilogram of coffee, a net kilogram must be delivered without including the weight of the packaging. It is permissible to include the weight of the packaging within the sold kilogram if the seller clarifies this to the buyer, provided that the weight of the packaging is known. It is not permissible for the weight of the packaging to be unknown and intended to be part of the quantity, nor is it permissible to count the weight of the packaging without informing the buyer.