How a barcode lookup works: the number is a key, not a price
A barcode never holds a price. Here is how a barcode lookup works at the till, and how to set up your own product file so every scan rings the right MRP.
The barcode holds only a number. The till reads that number, finds it in its product file, and shows the price stored in that row. Change the price in the file, not on the label.
How a barcode lookup works
The bars on a pack hold one thing: a number. They do not hold the price, the name, the weight or the brand. When a cashier scans the pack, the scanner reads the bars and turns them back into that number. It hands the number to the till. The till looks in its own product file for a row with that number. If it finds one, it shows the name and the price stored in that row. That is the whole lookup. The scanner reads. The till finds. The file answers.
Many first-time sellers assume the price travels inside the barcode. It does not. The same pack scanned in two shops can ring at two different figures from the same bars, because each shop keeps its own file. The number is a key. The price sits behind the door, inside the till.
What is printed in the bars
An EAN-13 symbol carries thirteen digits. The first few are a prefix, the middle block identifies the product, and the last one is a check digit the scanner uses to catch a misread. None of those digits mean ₹499 or 250 g. They are a label for one row in a database and nothing more.
The MRP printed in plain text on the pack is for the customer. It is a legal statement of the most the shop may charge. The bars beside it carry no part of that figure. A till that shows ₹499 on scan shows it because somebody typed ₹499 into a row and saved it.
Why the price lives in the till and not the label
Prices change more often than packaging does. A carton printed in March is still on shelves in November. If the price sat in the bars, every change would mean relabelling every unit in every shop. Instead the shop edits one row in its product file. From the next scan, every unit on the shelf rings at the new figure. One edit, one shop, done in a minute.
This also lets a shop run its own prices below MRP. A festival discount of ₹50 on a ₹499 pack is one edit to one row. The label on the pack stays as printed, and the law is kept because the till charges less than the printed figure, not more.
Build the product file before the first pack reaches the shelf
If you run a shop with your own till, open the product master in your billing software. Most call it an item list or product master. Each row needs five things: the barcode number, the product name as you want it on the receipt, the MRP, the tax rate and the unit. Enter the number by pointing your scanner at the pack with the cursor in the number field. The scanner types it for you, and it types all thirteen digits correctly every time. A hand-typed number with one wrong digit is a row the till will never find.
Do this for every product before it reaches the shelf, not after. A pack that arrives at the till with no row behind it is the single most common reason a queue stops.
If you are a brand sending stock to other people's shops, the shop builds the row, not you. What you send is a product sheet: the number, the product name, the MRP, the pack size, the net weight and the tax rate, one line per variant. Send it before the first carton, so the rows exist on the day the stock lands. Some chains want this in their own template. Tell us where you sell and we will say what that template usually asks for.
Change a price without touching a single label
Open the product master. Scan the pack into the search field so the right row comes up. Edit the MRP. Save. Then walk to the till and scan the same pack once. The screen should show the new figure. If it does not, the till is reading from a copy of the file that has not refreshed, and a restart of the billing app usually clears it.
If the price is going up, the new figure goes on new packs first. Old packs on the shelf still carry the old printed MRP, and the till may not ring above that. Sell the old packs through at the old row, then edit the row when the new packs arrive. If the price is going down, edit the row today and let the printed figure catch up on the next print run.
For stock in other people's shops, send an updated product sheet with a date the new price starts. The retailer edits their row on that date.
When the scan beeps and the screen shows nothing
A beep means the scanner read a number. A blank screen or an error means the till found no row for it. Three causes cover almost every case.
The first is a missing row. The pack was never entered, or it was entered under a different variant. Scan the pack into the search field and look for it.
The second is a wrong digit. Somebody typed the number by hand and one digit slipped. Pull the row up by name, then compare its number against the pack digit by digit. Fix it and save.
The third is a label the scanner cannot read at all, so there is no beep. This is a print problem. Print the symbol at full size, about 37 mm wide and 26 mm tall, in black bars on a white or pale ground. Leave a clear margin of at least 3 mm on the left and right of the bars. Do not print bars in red, do not print them over a photo, and do not let them wrap around a curve tighter than a soft-drink can. One sample label scanned at your own till before the full print run saves a reprint.
Which number goes on which pack
Every variant with its own price or size needs its own number. A 250 g pack and a 500 g pack are two rows in every till, so they need two numbers. Three flavours in one size are three numbers. A multipack of six is a fourth number, because the till must know that one scan means six units at one combined price.
Most products sold in India and across Asia, Europe and Africa use EAN-13. Products going into shops in the United States and Canada mostly use UPC-A, and the UPC-A numbers are a separate pack for that reason. The barcode guide walks through what each one does and does not do. If you are still unsure which one your shelf needs, tell us where you sell.
Order the numbers, then build the rows
Count your variants, order that many numbers plus a few spare for next season's sizes, and when the files arrive, type each number and its MRP into your product file or your product sheet the same day. Use code STARTUP10 for 10% off one order per account. It is valid until 31 December 2026 or for the first 100 uses on this site, whichever comes first.
Packs of EAN-13 numbers, with their prices and a note on what arrives in the files, are on the EAN-13 barcode page.
These are correctly formed, scannable numbers issued to you alone. A standard retail or POS scanner reads them: it checks the number's structure and its check digit, nothing more. Whether a marketplace or retailer accepts one is that channel's own decision — a small share of platforms and retailers look every number up in the global barcode database and will ask for a registered code instead. Tell us where you plan to sell and we will check it with you before you buy. Which barcode do I need?
