The UK's Internal Door Dimensions
For anyone undertaking a renovation, building a new home, or simply replacing a tired internal door in the UK, understanding standard door sizing is crucial.
While there isn't a single "one size fits all" dimension, a set of common measurements has emerged over time, with slight regional variations.
The Most Common UK Internal Door Size
In England and Wales, the most common internal door size is 1981mm (height) x 762mm (width) x 35mm (thickness). This is often referred to in imperial measurements as a 6ft 6in x 2ft 6in door. This dimension is widely stocked and fits the majority of existing door frames in older and more modern properties.
Scotland and Metric Doors
While imperial sizes still hold strong, particularly in older properties in England and Wales, Scotland and newer builds across the UK often lean towards metric door sizes. These typically feature a slightly increased height and thickness:
- Height: Scottish and metric doors are commonly 2040mm (approximately 6ft 8in) tall.
- Thickness: Metric internal doors are generally 40mm thick, providing a slightly more robust feel than the standard 35mm imperial doors.
- Width: While some metric widths align with imperial counterparts, common metric widths include 526mm, 626mm, 726mm, 826mm, and 926mm. Scotland's average door width is often slightly narrower, around 726mm.
Understanding Door Thickness
The thickness of an internal door is a key factor, impacting its stability, sound insulation, and fire resistance.
- Standard Internal Doors: Most internal doors in the UK are either 35mm (imperial) or 40mm (metric) thick.
- Internal Fire Doors (FD30 and FD60): Fire doors are designed to withstand fire for a specific duration.
- FD30 (30-minute fire rating): Typically 44mm thick.
- FD60 (60-minute fire rating): Usually 54mm thick.
Fire Doors are crucial for safety and must be installed with appropriate fire door frames, hinges, and intumescent strips.
Door Frames and Clear Opening Width
It's important to remember that door sizes refer to the door leaf itself. The door frame will add to the overall width and height of the opening. While there isn't a single standard door frame size, they are designed to accommodate common door dimensions. When measuring for a replacement door, it's essential to measure the inside of the existing door frame accurately at the top, middle, and bottom, and take the widest measurement.
Furthermore, building regulations, particularly for new builds and accessible dwellings, often specify a minimum clear opening width. This refers to the actual usable width when the door is open, taking into account the door's thickness, hinges, and stops. This clear opening width will always be smaller than the stated door width.
Even though UK door sizes can seem a bit mixed up because of old (imperial) and new (metric) measurements, knowing the usual sizes and how they differ across the country makes picking a door much easier.
In England and Wales, the most common door size you'll find is 1981mm high, 762mm wide, and 35mm thick. But in Scotland and newer homes everywhere, you'll often see slightly taller and thicker metric doors.
Always carefully measure your existing door frame before buying.