How big should a bathroom mirror be?

Choosing a mirror size for your bathroom, whether over a double vanity or a simple sink? While a mirror provides a practical purpose in a bathroom for checking your appearance, applying make up and for shaving, it also adds a decorative feature, often enhancing the role of a vanity unit as the focal point of the design. 

Bathroom mirrors can also be used to boost the feeling of space by bouncing light around the space. Though, mirror reflections need to be carefully planned in a bathroom since not everyone wants to see themselves in the bath or shower. 

So how to choose the perfect mirror to suit the size of room, where to hang it and how high should it be? We asked expert designers for their advice.

How big should a bathroom mirror be?

A typical wall-mounted rectangular bathroom mirror measures approximately H30in x W20in usually hung with its base at about 47in from the floor, so accommodating the basin vanity and a small upstand below. 

This is only a loose guide, as these measurements will vary according to the size of room, the height of the bathroom vanity and basin, the design of the mirror and your own height – the aim is to ensure that you can see your face easily and that the mirror’s position looks balanced in the room. 

Designer Chantel Elshout recommends selecting a mirror of about 30in tall as a general rule of thumb. ‘However, if the bathroom has high ceilings, I would go for a taller mirror to suit the proportions of the room,’ she explains. 

‘I also consider how balanced the mirror looks in proportion to the width of the basin and vanity, and whether we are planning wall lights on both sides of the mirror, because generally the mirror would be slimmer in this case.’ 

However, the rule of thumb is to choose a mirror width that is just shy (1 to 2in) of the width of your bathroom vanity's countertop.

Double mirrors

‘On a double vanity, we like to hang mirrors over both sinks to offer visual interest and balance within a scheme,’ explains designer Oana Sandu of Blakes London. 

Though the size of the bathroom mirrors as a pair should follow the rules above: ensuring the average height and width combined are in proportion to the vanity below and the ceiling height above.

‘Beautiful, well-proportioned mirrors act similarly to a piece of art within a room, reflecting light and adding depth and drama – think of it as wall jewellery,’ says Oana, who also recommends selecting mirrors fitted with heat pads to avoid condensation from steam build-up or ensuring good extraction.

How wide should your mirror be over your vanity?

As a general rule, a mirror (or combination of mirrors) should be an inch or two smaller than the width of the vanity counter. However, if you have wall lighting either side of your mirror, this can be factored in as part of the framing of the mirror. 

Hanging height and mirror frame shape

Designer Emma Merry emphasizes the need to factor in the height of the backsplash and faucet over the basin and vanity, if applicable.

‘We usually hang the mirror about 4in above the top of the backsplash,’ she says. Of course, much will depend on the individual setting and size of your room: the aim is to ensure that you can see your face centrally in the mirror.'

Nor do mirrors need to always be rectangular: remember, you are decorating with a mirror as well as using it for practical reasons. 

‘The circular mirror adds a certain softness and contrasts with the crisp angles of the vanity and adjoining shower screen,’ she explains. ‘Consider that a mirror, whilst being functional, can also act as a feature, so try using intricate shapes and larger or detailed frames to add drama to a space.’ 

Always ensure that frames are suitable for bathroom use and will not be damaged by steam or splashes.

Can a bathroom mirror be too big?

Of course, you can go wall-to-wall, floor-to-ceiling with mirrors to make a small bathroom look bigger, though this can make a bathroom feel a little soulless. The general rule is to choose one that's no wider than your bathroom vanity and approximately 30in tall. However, you can choose a larger mirror size strategically. 

In the bathroom above, the super-tall mirror functions as sink-width backsplash, too, allowing a small, naturally dark space to feel larger and brighter.