About KIX Barcodes
KIX (Klant Index, or Customer Index) is a 4-state postal barcode used in the Netherlands by PostNL to automate mail sorting. It is based directly on the British RM4SCC postal barcode standard but simplifies the implementation by omitting the start and stop guard bars and check digits, relying on the sorting scanner's optical character recognition (OCR) alignment.
How KIX Encoding Works
KIX encodes alphanumeric characters using four vertical states: Tracker, Ascender, Descender, and Full Bar. The encoded string represents the Dutch postcode (4 digits and 2 letters) followed by the house number and any house number addition. Because it lacks start/stop bars, scanners locate the barcode by identifying the alignment of the customer's printed address block.
Common Applications and Industries
KIX barcodes are printed by business mailers on letters and packages sent within the Netherlands. The barcode is typically printed directly below or above the recipient's address block on the envelope. PostNL sorting machines scan the KIX code to route mail automatically to the correct delivery person and street address.
Advantages & Limitations
KIX is very simple to generate and print, as it does not require complex start/stop patterns or parity check calculations. It fits neatly into the existing address label layout. The disadvantage is that without start/stop bars or built-in check digits, it requires clean printing and precise scanner calibration to prevent misreads.