Used by 700,000+ people
Free KIX barcode generator.
KIX is PostNL's 4-state barcode for a Dutch postal code and house number, printed under the address. Enter both as one string and download the bars.
How to create a KIX barcode
-
01
Join postal code, number and suffix
Drop the spaces and add an X before a suffix: Havendijk 156-2, 1231 GF becomes
1231GF156X2. -
02
Set the bar size in millimetres
Choose Module width 0.55 Millimeter, Resolution (dpi) 300 and text off: bars 0.51 mm wide and 5.67 mm high, within PostNL's ranges.
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03
Print it under the address
Place it 2–15 mm under the last address line, dark on light. The image has no margin: keep 2 mm clear all round in your layout.
What is a KIX code?
The KIX code (klantindex) puts a Dutch address into bars: postal code, house, PO box or reply number, and suffix. PostNL's sorting machines read it where the written address fails. From 18 August 2025, PostNL's design conditions drop the KIX from the address; the Briefcode is still set in the KIX font.
Where KIX goes: Dutch letters and reply cards
PostNL's 2012 handbook puts the KIX on the same carrier as the address, such as the label or the reply card. On reply cards with a shared address side, a 70 mm address field is enough: a reply-number KIX has only 11 characters, about 50 mm.
The sender address carries no KIX. For Track & Check letters, Mijn PostNL returns a Briefcode or 2D matrix code per address.
Bar sizes PostNL's sorting machines read
Each character is four bars, two reaching up and two down from a short tracker. Bars are 0.38–0.63 mm wide, gaps at least 0.4 mm, at 20–24 bars per 25.4 mm.
Outside these sizes, PostNL finds KIX codes unreadable for automatic sorting. Gaps between characters must equal gaps within one, which condensed or expanded spacing can break.
From one address to a mailing list
Without an account, the generator draws one KIX at a time as GIF, PNG or JPG; SVG and higher print resolution come with a plan. A mailing list goes into a data sheet after a free sign-in.
In TEC-IT software, KIX is symbology 90. TBarCode SDK prints it from your applications, TFORMer Server unattended from ERP data; TBarCode API returns it by URL.
KIX at a glance
- Specification
- PostNL, Handleiding KIX code (2012)
- Characters
- 0–9 and A–Z, at most 18
- Check digit
- None
- Bar heights
- Tracker 1.02–1.52 mm, ascender and descender 1.60–2.16 mm
- Print contrast
- PCR at least 40%
- Clear zone
- 2 mm all round
What goes into the KIX content
| Part | Length | Example |
|---|---|---|
| Postal code | 4 digits, 2 letters | 1231GF |
| House, PO box or reply number | Up to 5 digits | 156 |
| Separator before a suffix | X | X |
| Suffix | Up to 6 characters | 2 |
Mistakes that make a KIX unreadable
- Text off with Module width at Fit. The bars stretch to over 8 mm, beyond PostNL's heights; set a millimetre module width first.
- KIX line in the address type size. Print a scalable KIX font at 10 pt.
Frequently asked questions
Learn more about KIX.
Is the KIX code still required by PostNL?
Do I need a KIX code on mail abroad?
How long can a KIX code be?
What does KIX stand for?
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