Measuring Door Thicknesss

Door profile thickness refers to the total depth of a door slab, measured from the external face to the internal face, at the point where the lock and handle are fitted. It’s a common specification for uPVC, composite, and aluminium doors, where hardware passes straight through the door rather than mounting on the surface.

When people search this term, they’re usually trying to confirm whether a replacement lock, handle, or euro cylinder will physically fit through their door.

 

Typical Door Thickness Sizes

Most modern residential doors fall into a small range of standard thicknesses:

• uPVC doors: commonly around 44–48mm
• Composite doors: often 44mm, sometimes thicker depending on construction
• Aluminium doors: typically 44–50mm+

Exact thickness can vary by manufacturer, which is why measuring your own door is always safer than guessing.

Why is Door Profile Thickness Important?

Door profile thickness directly determines the correct length of through-door components. Using the wrong lengths can cause poor operation, security issues, or visible fitting problems.

• Euro cylinders: thickness helps define the inside/outside cylinder split so it sits flush on both sides. (more information on Euro cylinder projection)
• Handle spindles: the spindle must be long enough to pass through the door and gearbox without bottoming out.
• Fixing screws: screws must clamp the handles securely without stripping threads or pulling loose.

How to Measure Door Profile Thickness

Measuring door thickness is straightforward and only takes a minute:

• Measure straight across the door from the external face to the internal face.
• Take the measurement near the handle or lock area.
• Exclude decorative trims unless the hardware passes through them.

This measurement is especially useful when selecting a euro cylinder or checking whether a handle set includes a suitable spindle length.

How It Affects Lock Replacement

Door profile thickness doesn’t usually affect which multipoint lock strip you need, but it plays a key role in everything that passes through the door. Many replacement issues happen when the lock body is correct but the supporting components aren’t sized for the door.

When gathering measurements, it’s best to consider thickness alongside other dimensions.