VELUX Roof Window Size & Code Guide

Understanding VELUX Roof Window Size Codes

VELUX roof windows use a simple code system such as MK04, CK02 or SK06. Each code corresponds to a specific frame width and height, making it easy to identify, replace or specify the right size.

The first two letters indicate the width of the window, while the two digits indicate the height. Once you know the size code, you can quickly match windows, flashings and blinds.

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VELUX Roof Window Size Chart

Use this chart to find the dimensions of common VELUX roof window sizes:

VELUX Size Code	Width (mm)	Height (mm)	Typical Applications
CK02	550	780	Bathrooms, hallways, small rooms
CK04	550	980	Compact loft spaces
FK06	660	1180	Bedrooms, kitchens
MK04	780	980	Loft conversions, general living spaces
MK06	780	1180	Living rooms, larger lofts
PK06	940	1180	Bright, open-plan rooms
SK06	1140	1180	Large loft rooms
UK08	1340	1400	Maximum daylight in big spaces

If you are replacing an existing VELUX window, the size code is usually printed on a small plate at the top of the sash when the window is opened.

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Choosing the Right VELUX Size

When deciding which size to use, consider:

• Room size: Larger rooms generally benefit from larger or multiple windows.
• Ceiling height: Higher ceilings may suit taller window sizes.
• Furniture layout: Ensure handles remain easy to reach.
• Daylight needs: Bedrooms vs. living rooms vs. home offices.

For full buying considerations, see our VELUX Roof Window Buying Guide.

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Matching Windows, Glazing, Flashings & Blinds

Once you know the size code, you can match:

• Roof windows: e.g. GGL MK04, GGL MK06.
• Glazing options: Choose performance to suit each room – see our VELUX Glazing Options Guide.
• Flashings: EDW, EDL, EDP, etc., sized to the same code – see our VELUX Flashing & Installation Guide.
• Blinds: Every VELUX blind references a size code – see our VELUX Blinds & Shading Guide.

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Related VELUX Guides

• VELUX Roof Window Buying Guide
• VELUX Glazing Options Guide
• VELUX Flashing & Installation Guide
• VELUX Installation Costs & Considerations
• How to Measure Roof Pitch for VELUX Windows
• VELUX Roof Window Replacement Guide

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