Make shopping for your new windows easy with our VELUX Window Sizes Guide. Our VELUX  can often be confusing with the range of sizes, model numbers and window codes that are applied to each window. But with our easy to navigate VELUX chart you can discover the exact window you need in minutes.

VELUX Size Guide

If you are looking to replace an existing VELUX roof window you can use the VELUX size guide to discover which VELUX new generation size code relates to your old roof window code (see below). To explain, if your current VELUX brand window has a code of GGL2 then your new VELUX brand window would be the MK08. For further explanation, you can review Velux Window Codes below. 

VELUX Window SizesVELUX Sizes explained


A guide to your VELUX Window Codes

VELUX are always improving their products to ensure they maintain the high quality which VELUX are known for. These continuous improvements over the years obviously results in some of the older style VELUX brand windows becoming out of date in terms of the off-shelf support.

However, this is not a problem. The new off-shelf VELUX flashings can be made to fit these older windows in many circumstances.

Old VELUX Window Sizes, Serial Numbers and Number Codes

Below is a list of the window sizes and the variety of codes which they may have on them, depending on when the window was purchased. 
Remember window sizes are for the external window frame not internal measurements.

  • Window size 55 (W) x 78 (H) code 102 or CO2 or CKO2
  • Window size 55 (W) x 98 (H) code 104 or 6 or CO4 or CKO4
  • Window size 78 (W) x 98 (H) code 304 or 1 or MO4 or MKO4
  • Window size 66 (W) x 118 (H) code 206 or 5 or FO6 or FKO6
  • Window size 78 (W) x 118 (H) code 306 or 14 or MO6 or MKO6
  • Window size 78 (W) x 140 (H) code 308 or 2 or MO8 or MKO8
  • Window size 138 (W) x 98 (H) code 804 or 7 or UO4 or UKO4
  • Window size 114 (W) x 118 (H) code 606 or 4 or SO6 or SKO6
  • Window size 98 (W) x 160 (H) code 410 or 3 or P10 or PK10
  • Window size 134 (W) x 140 (H) code 808 or 8 or UO8 or UKO8

Where are the VELUX Brand Windows Codes Located?

The VELUX brand window codes are found on the top right-hand edge of the roof window when you open it. The data plate tells you the type of window and the window size shown through the code. As shown below in the example, 304 would be 78cm x 98cm and the bottom window code 4 would be 114cm x 118cm.

VELUX codes

For further information on Roof Window Repairs, fitting a new flashing set to an old roof and VELUX windows or how to replace old VELUX flashings, please visit here

If you have any further questions after reading this guide, feel free to contact VELUX directly on 01592 778 225.

Besides price…
why else would you choose YARD?
  • Roof Windows is all we do – we love what we do
  • We’re nice to deal with
  • We get a kick out of helping our customers
  • We make sure we fully understand your project
  • So, we can offer you the best window options
  • We believe we’re exceptionally good at this
  • We’ll keep your tradesmen or installer happy
  • We always ask the right questions before you buy
  • If things go wrong – we take a pride in sorting

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