Most bathroom mirrors are hung wrong before the box is even opened, because the size was wrong at checkout. Too wide and the mirror crowds your sconces and reads like a wall of glass. Too small and it floats above the vanity like an afterthought. The good news is that bathroom mirror size follows a handful of proportion rules that hold up in almost any room, from a condo ensuite in Vancouver to a bungalow bath on the Prairies to a century home in Halifax.
Rule one: never wider than the vanity
The mirror should be equal to or narrower than the vanity below it. Equal width gives a clean, built-in look and suits frameless or slim-frame designs. Slightly narrower, with roughly 5 to 10 cm of wall showing on each side, reads more like furniture and leaves breathing room for wall colour and lighting. A mirror wider than the vanity almost never looks intentional, and it has a habit of colliding with the light switch or towel bar you forgot was there.
If the cabinetry is not settled yet, size that first. Our bathroom vanity size guide covers the standard widths, and once the vanity is fixed the mirror decision gets easy. The table below is a reliable starting point.
| Vanity width | Rectangular mirror width | Round mirror diameter |
|---|---|---|
| 24 in (61 cm) | 20 to 24 in | 20 to 24 in |
| 30 in (76 cm) | 24 to 30 in | 24 to 28 in |
| 36 in (91 cm) | 28 to 36 in | 26 to 32 in |
| 48 in (122 cm) | 36 to 48 in | 30 to 36 in, or go rectangular |
| 60 in double (152 cm) | One 48 to 56 in, or two mirrors | Two 24 to 28 in rounds |
Height: work from eye lines, not habit
Width gets all the attention, but height is what makes a mirror feel right day to day. The centre of the mirror should sit close to eye level for the people who actually use the room. For most households that lands somewhere between 150 and 165 cm off the floor, and if two adults of different heights share the sink, split the difference and choose a taller mirror so both are covered.
Two more checkpoints keep things tidy. The bottom edge should clear the faucet by at least 15 to 25 cm so splashes and tall spout arcs do not fight the glass. And the top edge should stop short of the ceiling: on a standard 8 ft ceiling, leaving a visible band of wall above the mirror keeps the room from feeling capped, while 9 and 10 ft ceilings can carry a much taller mirror, or even a full-height panel, without looking heavy.
Round mirrors over single vanities
Round mirrors are forgiving because there are no corners to line up with anything, but diameter still matters. Aim for roughly two thirds to three quarters of the vanity width, which is why 24 to 32 in rounds are the workhorses over most single vanities. Smaller starts to look like a porthole; close to full vanity width, and the circle crowds the backsplash and the light above it.
A frame earns its keep here. A thin metal ring in black or brushed brass sharpens a minimalist room, while decorative framed rounds from a house like Renwil, the Montreal-based decor brand, can carry a powder room almost single-handedly. Powder rooms are also the one place where the rules loosen up: with no daily grooming happening, you can size a round mirror as art rather than equipment.
Double vanities: two mirrors or one wide sheet?
Over a 60 or 72 in double vanity you have two legitimate options, and honestly, both work. It comes down to how the room is used.
- Two mirrors define his-and-hers stations, add rhythm to a long wall and let you centre each mirror over its own sink. Keep each mirror narrower than its sink station and leave at least 10 to 15 cm of wall between the pair, ideally with a sconce in that gap.
- One wide mirror bounces more light, makes a modest ensuite feel larger and forgives sinks that are not perfectly symmetrical. It suits contemporary rooms and works best frameless or with a very slim frame.
The mistake to avoid is two mirrors sized so generously that the gap between them shrinks to a sliver. If the math leaves less than about 10 cm between the pair, one wide mirror will look far more deliberate.
Mirrored cabinets: when the mirror should work for a living
In a small bathroom, the wall above the vanity may be the only storage you have, and a mirrored cabinet turns it into shelving without changing the look of the room. Swiss-engineered lines like Sidler are the benchmark here, with mirrored interiors, adjustable glass shelves and options like integrated lighting and interior outlets for razors and toothbrushes.
Sizing rules stay the same as for a flat mirror, with two additions. Recessed cabinets need real wall depth, so confirm the cavity is free of plumbing and wiring before you commit, and be cautious about recessing into an exterior wall in a Canadian climate, where cutting into insulation and the vapour barrier is a job for your contractor to assess, not an afternoon guess. Surface-mounted versions avoid all of that at the cost of projecting into the room. For any lighted mirror or cabinet, hardwired or plug-in, look for a Canadian electrical certification mark such as CSA or cULus on the spec sheet.
Lighting changes the math
Mirror and lighting decisions should be made together, not in sequence. If you are flanking the mirror with wall sconces, the mirror needs to be narrow enough to leave comfortable clearance on each side, usually a few centimetres beyond the sconce backplate at minimum. If the light mounts above, the fixture should be no wider than the mirror below it. Backlit and front-lit LED mirrors solve the clearance problem entirely, though a dedicated bathroom light still renders skin tones more honestly for makeup and shaving.
One last practical note for Canadian buyers: mirrors ship as fragile glass freight, so whether the truck is headed to BC or Newfoundland, inspect the carton and the glass on delivery before signing anything. When you are ready to compare shapes and sizes side by side, browse the full bathroom mirror collection alongside your shortlisted vanity so the pairing is decided as a set.
Frequently asked questions
What size mirror should go over a 36 inch vanity?
A rectangular mirror between 28 and 36 in wide, or a round mirror of 26 to 32 in diameter, will look proportionate. Match the vanity width exactly for a built-in look, or leave a few centimetres of reveal on each side if you want the mirror to read as a separate piece.
How high should a bathroom mirror be hung?
Centre it near eye level, typically 150 to 165 cm off the floor, with the bottom edge at least 15 to 25 cm above the faucet. In shared bathrooms, choose a taller mirror rather than compromising the centre height for one person.
Is one big mirror or two mirrors better over a double vanity?
Two mirrors suit defined stations and traditional rooms; one wide mirror maximizes light and forgives off-centre sinks. If two properly sized mirrors would leave less than about 10 cm of wall between them, a single wide mirror is the cleaner choice.
Can I recess a mirrored cabinet into any wall?
No. The cavity must be free of plumbing, wiring and ductwork, and exterior walls in Canada deserve extra caution because recessing can disturb insulation and the vapour barrier. When in doubt, choose a surface-mounted cabinet, which installs on any sound wall.
