Units, packs, prices and barcodes

A stationery shop sells the same pencil loose, by the dozen and by the box, and buys it by the carton. BooksPOS keeps one stock figure for the pencil, counted in pieces, and lets each pack have its own price and its own barcode. This guide shows how to set up units and packs, how prices for packs work, and what the till does with them.

The base unit and packs

Every item has a base unit with factor 1. It is how stock is counted:

• a new book starts with PCS, named Copy;
• a new stationery item starts with PCS, named Piece.

A pack is any other unit of the same item: a packet, a dozen, a box, a ream, a carton. Its factor says how many base units it holds, for this item only. A box of pencils may hold 12 while a box of chalk holds 100.

Stock is always kept in base units. If you receive 10 boxes of 12 pencils, the stock is 120 pieces. Sell 2 boxes and 3 loose pencils, and 93 are left. Take one pencil back, and there are 94. Nothing is counted twice, whichever unit you sell in.

How to add a pack to an item

1. In Catalog, open the item with Edit (or create it with New book or New stationery item).
2. Under Units, prices and barcodes, choose Add unit. The first extra unit starts as BOX, Box of 12, factor 12: change them to suit.
3. Fill in the row:

4. Choose Save item.

A unit that is bought but not sold (a carton, for example) needs only Bought in this unit. The till then will not offer it.

The item form. Units, prices and barcodes on one item; tax rate as the owner enters it. Screenshot of the current build (28 Sep 2026), synthetic demo data.

Prices for packs

• A pack's price is its own figure. A dozen may cost less than twelve single pieces; BooksPOS does not force it to add up.
• If a pack has no price of its own, the till uses the base unit's price times the factor, and the line says From unit price.
• Prices are dated. A change applies from the day it is saved; bills already made keep their price.
• Price lists, quantity breaks and promotions can change the price further. See Price lists, quantity breaks and promotions.

Barcodes

• One item can carry several barcodes: the maker's barcode, an old label from your previous system, a distributor's code.
• The ISBN of a book and the item's own SKU are added as barcodes automatically.
• A pack's own barcode rings up the pack, not one piece: scanning the barcode printed on a box puts a box on the bill.
• If one barcode is found on two items (often two editions of one title), the till asks which one the customer is holding. It never guesses.
• A label for a pack can only carry the pack's own barcode, because the SKU would ring up a single piece. See Printing barcode labels.

At the till

The Unit column on each bill line lists the units the item is sold in. Scanning or searching adds the item in its base unit (or in the pack whose barcode was scanned); change the unit on the line if the customer takes a box. The quantity and the price follow the unit. A return can be made in a different unit from the sale, for example one pencil back from a box.

Rules worth knowing

• A pack's size cannot change once it has been used. If a box of 12 has been bought or sold, changing it to 10 would rewrite history, so it is refused: "Box of 12 has already been used in stock documents; add a new unit instead of changing its size." Add a new unit, such as BOX10, and stop selling the old one.
• Units cannot be removed. Untick Sold in this unit and Bought in this unit instead. Only a new unit that has not been saved yet can be removed.
• Opening stock and imports are in base units. A shelf with 5 boxes of 12 is entered as 60.

Common questions

A customer wants half a dozen. What do I do?

Sell 6 in the base unit. If you often sell half dozens, add a unit with factor 6 and its own price.

Can a ream and a single sheet be the same item?

Yes, if you sell loose sheets. Make the sheet the base unit and the ream a unit with factor 500 (or whatever your ream holds).

Why does the pack price on the bill differ from twelve times the piece price?

Because the pack has its own price. That is usually intended: a dozen is cheaper per piece. If you would rather it followed the piece price, leave the pack's retail price empty.

The supplier sends cartons of 10 boxes. Do I need a carton unit?

Only if you receive in cartons. Add a carton unit with the right factor in base units (for example 10 boxes of 12 = 120) and tick only Bought in this unit.

Related guides

• Adding books and stationery items
• Billing at the till
• Printing barcode labels
• Price lists, quantity breaks and promotions