VELUX size guide

How to Find Your VELUX Window Code

Every VELUX roof window carries a code that tells us exactly which blind fits it. This guide shows you where to find it, how to read it, and how to turn it into the right made-to-measure blind.

Where the VELUX identification plate is

Open the roof window fully and look along the top edge of the sash. VELUX fits a silver identification plate there, and it carries everything we need: the model prefix, the size code and the manufacturing details.

VELUX publishes its own guidance on where the type sign sits and how to read it — see the primary sources listed at the end of this guide.

Reading the code safely

Read the plate only from a safe, stable position, with both feet supported and without stretching or leaning. Follow VELUX's own guidance on finding product information safely rather than improvising with ladders or furniture.

You can use a phone camera to photograph the plate, but only from that same safe, stable position. If the plate cannot be reached or photographed safely, do not try: send us a safe photo of the window taken from floor level, or contact us and we will identify the size with you.

Prefix versus size code

A VELUX code has two parts. The prefix — GGL, GGU, GPL, GPU, GHL, GXL and so on — describes the window model and material. The size code that follows — MK04, SK06, M04, P10, 304 — describes the glass size.

The size code is what determines your blind. The prefix helps us cross-check that the size is plausible for your window, which is why we ask for both when you order.

Current, single-letter and legacy numeric codes

Modern windows use two-letter codes such as MK04, SK06 and UK08. Older windows use single-letter codes such as M04, S06 and P10. Windows from the 1990s and earlier use purely numeric codes such as 304, 606 and 804.

All three families are still fitted across Ireland and all three are covered here. Read the plate exactly as printed — the difference between M04 and MK04 is a different window.

Every VELUX size code we make blinds for

We currently make blinds for 69 VELUX size codes. Open your code below to see every blind that fits it. Order to the code on the plate — no measuring needed.

Code unreadable, damaged or missing?

Plates fade, get painted over or go missing after a re-roof. If you cannot read yours, send us a photo of the window and the plate through our contact page, or email info@bizzyblinds.ie, and we will identify the size with you.

If you are not certain, send us your full code or a photo of the identification plate and we will confirm the fit before you order.

Common questions

Where exactly is the VELUX window code?

On the silver identification plate along the top edge of the sash, visible when the window is opened fully. It shows a model prefix such as GGL followed by a size code such as MK04.

What is the difference between the prefix and the size code?

The prefix (GGL, GGU, GPL, GPU and so on) identifies the window model and material. The size code (MK04, S06, 304 and so on) identifies the glass size, and that is what determines which blind fits.

My window code is a plain number like 304 — is that still valid?

Yes. Numeric codes come from earlier VELUX roof windows and are still widely fitted in Ireland. Because they pre-date the modern coding system, double-check the plate before ordering.

What if I cannot read the identification plate?

Send us a photo of the plate or the window through our contact page, or email info@bizzyblinds.ie, and we will confirm the size code with you before you order.

Primary sources

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VELUX® is a registered trademark of VKR Holding A/S. Bizzy Blinds is an independent supplier of aftermarket blinds compatible with VELUX roof windows and is not affiliated with VELUX.