Scale barcodes: how to sell loose goods without pricing mistakes

Operations · 2026-10-22 · 5 min read

A label from a scale holds an item code and a weight or price. Here is how it is read, and why the format must be set to match your own scale.

What is on a scale label

The label scales used in coffee shops, cake shops, or vegetable stalls print an EAN-13 barcode on every pack. That barcode is not an ordinary factory barcode. According to GS1, the body that manages barcode numbers worldwide, barcodes starting with 02 or 20 to 29 are numbers for restricted use inside a particular shop or country. Inside is an item code, then the weight or the price of that pack.

The meaning of each digit is not the same everywhere. GS1 leaves it to each country’s GS1 organisation, and in practice the label is printed according to the scale settings you choose yourself. Two scales of different brands in the same shop can print different formats.

Why the format must not be guessed

Imagine the till assumes the last five digits are the price, while your scale writes the weight in grams. 512 grams of coffee would be read as a price of 512 rupiah. A mistake like this does not show on screen when the till is busy, and is only found when the end-of-day report does not match the drawer.

That is why Lamxo does not use a built-in format for each country. You set the format for each outlet: the prefix used, the position of the item code, whether the number on the label is a weight or a price, and how many decimal digits it has. The settings screen has a box for scanning one sample label, and the reading is shown before you save, so you can compare it with the numbers printed on the label.

What happens when it is scanned

The till checks the barcode’s check digit, matches the prefix, then looks up the item code in the product data whose unit is grams or millilitres. If the label holds a price, that price is used. If the label holds a weight, the weight is multiplied by the price per kilogram that you set. Stock goes down by the weight, so coffee stock is recorded in grams, not in packs.

If the prefix matches but the item code is not recognised, Lamxo declines with the message "Weighed item not recognised". The item is never sold at zero price just because its data does not exist yet.

The limits

Lamxo reads labels already printed by the scale; a scale cannot yet be connected directly to the till by cable. Label formats differ between scales, so you set the format to match your scale.