Last updated: 26 September 2026 · All guides
When a courier's scanner cannot read your label, the parcel gets set aside, keyed in by hand, or sent back for a new label. Any of those can delay the shipment. The good news is that almost every unreadable barcode comes down to one of a handful of causes, and most are fixed in the print settings.
A quick test before you pack: scan one label from each batch with a barcode scanner app on your phone. If it reads cleanly from a normal distance, the courier's scanner will almost always read it too.
1. The label was shrunk when printing
This is the most common cause. A barcode works by the exact widths of its bars and spaces. When a label is scaled down, for example by printing a full A4 marketplace sheet onto a 4×6 label, or by leaving "Fit to page" on, every bar gets thinner and the narrowest ones can disappear altogether.
Fix: crop the label to its real size first with the Flipkart or Meesho crop tool, then print at Actual size / 100%.
2. The print is too light
Grey, patchy bars do not give a scanner enough contrast. On a thermal printer this usually means the darkness setting is too low or the labels are poor quality. On an inkjet or laser printer it means low ink or toner, or a "draft" or "eco" print mode.
Fix: raise the darkness a step or two in the thermal driver, or switch off draft mode and replace the cartridge.
3. The print is too dark
The opposite problem also happens. With darkness set too high, the heat spreads and neighbouring bars bleed into each other, so the gaps between them close up.
Fix: lower darkness, or reduce print speed, until the gaps between bars are crisp and white.
4. White lines run through the barcode
Thin white lines running the full length of every label point to the printhead. A speck of dirt or label adhesive on the head stops that one dot from heating, so the same line is missing on every print. If the line cuts across the bars, it can break the barcode.
Fix: clean the printhead following the manufacturer's instructions, usually with an isopropyl alcohol swab once the head has cooled. If a line stays after cleaning, that part of the head may be worn out.
5. The blank margin around the barcode was cut off
A barcode needs a strip of blank space on its left and right, called the quiet zone, so the scanner can tell where it starts and ends. If a label is cropped too tightly, or the barcode runs right to the edge of a hand-cut label, the scanner may not find the start.
Fix: leave the white margin around the barcode intact when cutting, and do not overlap another label or sticker onto it.
6. Shiny tape over the barcode
Clear packing tape laid over a barcode can reflect the scanner's light straight back, especially under strong lights in a sorting hub. Some scanners cope with it; many struggle.
Fix: tape around the edges of the label rather than across the barcode. If a label must be fully covered, for example in wet weather, a matte tape reflects much less.
7. The label is creased or bent round an edge
A label folded over the corner of a box, or wrinkled on a soft poly mailer, bends the bars out of a straight line. Scanners need the barcode to be flat.
Fix: stick the label on the largest flat face of the parcel. On soft packaging, smooth it out completely, and choose a flatter area away from seams.
8. The label has faded
Direct thermal labels darken with heat, so heat and strong sunlight keep darkening the whole label over time, until the bars and background lose contrast. Labels printed well ahead of dispatch, or parcels left in a hot vehicle or a sunny window, are the usual victims.
Fix: print labels close to the time of dispatch, and store both blank rolls and printed labels somewhere cool and out of the sun.
A checklist before every batch
- The PDF is cropped to the label, not a full A4 sheet.
- Print scale is Actual size / 100%.
- Bars are solid black with crisp white gaps.
- No white lines run through the barcode.
- The margin on both sides of the barcode is intact.
- One label from the batch scans with a phone app.