How To Tell If Your Hotel Mirror Is Actually A Two-Way Mirror

Mirror, mirror on the wall, who is the most stalker-y of them all?


Dr. Beccy Corkill


Dr. Beccy Corkill

Custom Content Manager

Beccy is a custom content producer who holds a PhD in Biological Science, a Master’s in Parasites and Disease Vectors, and a Bachelor’s in Human Biology and Forensic Science.

Custom Content Manager

Modern luxury bathroom interior with double sink and big mirror on wall.

I'm not paranoid... you are paranoid!

Image credit: ben bryant/

Are you a paranoid Penny or a nervous Neville when you go into a hotel room? Have you ever looked at a mirror with suspicion and recalled all those movies with two-way mirrors, and wondered how to check what you are looking at? Well, there are a few tricks for that!

What is a two-way mirror?

The first two-way mirror was patented in the US back in 1903. These are panels that look like mirrors on one side, but are pretty much tinted windows on the other. Think back to all those crime shows, specifically the interrogation room scenarios.


Often these panels can be referred to as either two-way or one-way mirrors, half-silvered mirrors, or one-way glass. While there are many names for it, the better terminology is probably transparent mirror. These are laminated glass products that have been encased in a thin layer of metal, which results in a mirrored surface that reflects some of the light.

Fingernail trick

There is one very simple test that you can do, and that involves placing your fingernail against the reflective surface. If there is a gap between your fingernail and the image of the nail, then congratulations! You have a bona fide genuine mirror.

More upsetting is the other scenario. If your fingernail directly touches the image of your nail, this means that it is probably a two-way mirror.

This test works due to where the reflective part of the mirror is. In a transparent mirror the reflective part is often laid right at the surface; with an actual mirror, there is often a layer of clear glass to protect the reflective part.


There are times that the reflective surface is laid first, but these are normally expensive mirrors, and you are not likely to encounter these in hotels.

This trick does have some drawbacks, as the unpracticed observer could mistake an ordinary mirror for a transparent one. Judging whether an object is placed up against a mirror can be affected by the angle or size of the mirror, the type of object used, and the lighting present.  

Mirror placement

Often transparent mirrors are not hung on the wall, but actually set into it. If there is a wall behind the mirror, then chances are that it is an actual mirror.

The lighting placement is also important. The lighting where the hidden observers are needs to be darker than on the person in front of the mirror. If you press your face up against the mirror and cup your hands around your eyes (blocking out the light from the room you are in), you can sometimes see through the transparent mirror.

Audio test

Gently tapping your fingers against the mirror can also give a clue. Mirrors typically have backing and are placed in front of walls. This means a gentle finger tapping will produce a dull thud, whereas transparent mirrors would make a hollower sound.  

Mirrors be crazy

Mirrors are crazy objects that are determined to break our brains at their convenience. People commonly scratch their heads over how a mirror can see an object that is hidden by a piece of paper. Luckily, we have made a video answering that question.

People are also confused to learn that mirrors don’t really flip things left to right… You guessed it, we have a video answering that question as well.

Mirrors are strange objects, but hopefully with these tricks you can be a bit less paranoid in hotels… maybe.


  • tag
  • mirrors,

  • safety,

  • hotel,

  • surveillance,

  • mirror test,

  • creepy