Bathroom mirror sizes & shapes guide
Bathroom mirror sizing is the most commonly regretted decision in the bathroom mirror category. It's also one of the simplest to get right. The rule is one number applied to one measurement: the mirror width should sit at 70–80% of the vanity width below it (60–70% for round mirrors). That's the whole rule. Everything else in this guide is how to apply it correctly, what shape options exist within that constraint, how mounting height interacts with the sizing decision, and how the choice of shape and size connects to the finish and feature decisions that follow.
Round vs oval vs rectangle vs arched
The bathroom mirror shape decision sets the room's visual register before anything else (finish, lighting, even tile) registers. Four shape families dominate the modern UK bathroom mirror market:
| Shape | Visual effect | Best room style | Best vanity match |
|---|---|---|---|
| Round | Softens rectilinear bathroom geometry | Modern, transitional, country | Most vanity widths 500mm+ |
| Oval | Sits between round and rectangular | Modern, transitional | Narrower vanities (500–700mm) |
| Pill (elongated oval) | Horizontal soft shape | Modern | Wider vanities (700–1000mm) |
| Rectangular | Maximises reflective area; classic | Any style; most versatile | All vanity widths |
| Arched (rectangle with curved top) | Character; feature-piece | Modern with traditional gesture | Wider vanities (700mm+) |
Three practical principles when choosing shape:
- Round breaks the line. Bathrooms are full of straight horizontal and vertical lines (vanity rim, basin edge, taps, doorways, tiled walls). A round mirror is the first piece of geometry that breaks that pattern, and the visual relief is usually welcome. This is why round has become the modern default.
- Rectangular maximises useful reflection. For bathrooms where the mirror is genuinely used as a working surface (makeup, shaving, hair-styling), rectangular gives the most face-level reflective area per unit of mirror width. Important for grooming-heavy bathrooms.
- Shape doesn't constrain finish or feature. Round, oval, rectangular and arched mirrors all come in every finish (black, brass, chrome, frameless) and every illumination option (LED, backlit, demister). The shape decision and the finish/feature decisions are independent.
What size mirror over a vanity?
The rule of thumb: mirror width should sit at 70–80% of the vanity width below (60–70% for round mirrors, where the lower proportion suits the circular shape better). The reasoning: a mirror sized at the full vanity width reads as oversized and dominates the vanity; a mirror sized below 60% reads as orphaned and undersized; the 70–80% range is the sweet spot where the mirror sits in deliberate proportion to the vanity below.
The full sizing table for standard UK vanity widths:
| Vanity width | Rectangular mirror width (70–80%) | Round mirror diameter (60–70%) |
|---|---|---|
| 400mm (compact cloakroom) | 280–320mm | 240–280mm |
| 500mm (cloakroom) | 350–400mm | 300–350mm |
| 600mm (standard family) | 420–480mm | 400–450mm |
| 700mm (larger standard) | 490–560mm | 450–500mm |
| 800mm (larger family) | 560–640mm | 500–600mm |
| 900mm (transitional) | 630–720mm | 550–650mm |
| 1000mm (master single) | 700–800mm | 600–700mm |
| 1200mm+ (double-basin) | Two mirrors aligned to each basin | Two round mirrors at 500–600mm each |
For double-basin vanities (1200mm+), two separate mirrors aligned to each basin position usually works better than one wide mirror spanning both. Single wide mirrors over double basins can look orphaned (centred between the basins rather than over either) or stretched (wider than the visual proportion supports).
Mounting height and placement
Mirror height matters as much as width for the final visual result. The principles for mounting height:
- Centre the mirror on the household eye level. For UK households (average adult eye height 1500–1700mm), the mirror centre typically sits at 1550–1650mm above the floor. For families with significantly different heights, compromise at the average; for single-user bathrooms, mount to the user's preference.
- Bottom edge 100–200mm above the basin or splashback. Leave a small visible gap between the basin rim/splashback and the mirror's lower edge; mounting too low or too high both look wrong. The 100–200mm gap is the conventional UK standard.
- Top edge below ceiling fittings. The mirror should clear ceiling-mounted bathroom lighting, extractor fans, and any decorative cornice by at least 100mm. Mirrors that touch ceiling fittings look cramped and break the wall's vertical rhythm.
For lit mirrors specifically, position the mirror so the LED illumination falls on the face at user height rather than above it. A mirror mounted too high relative to the user puts the LED ring above eye level, which defeats the purpose of front-lit illumination. If different household members are very different heights, prioritise the height of the user who does most grooming at the mirror.
Sizes in mm at a glance
Standard bathroom mirror widths and diameters available in most Plumbworld ranges:
- Compact range (300–500mm). Cloakroom mirrors, ensuite mirrors, supplementary mirrors elsewhere in the bathroom. Round, oval, and rectangular all available in this range.
- Standard range (500–800mm). Family bathroom mirrors for standard vanities. The bulk of the bathroom mirror market sits in this range. All shapes available; all finishes available; LED options available across.
- Large range (800–1200mm). Master bathroom mirrors, statement pieces, mirrors for wider vanities. Rectangular dominates this size range (round and oval at 800mm+ start to read as oversized); LED and demister common.
- Feature range (1200mm+). Genuinely large statement mirrors. Often supplied as bespoke or made-to-measure rather than off-the-shelf. Two-mirror arrangements over double-basin vanities also fit here.
Browse large bathroom mirrors for the 800mm+ range, or small bathroom mirrors for the compact options under 500mm.
Now choose a finish and features
With size and shape settled, the remaining decisions are finish and features. These are independent decisions: any shape works in any finish, and any shape can include LED, backlit, demister, or other features. The shape and size you've chosen here doesn't constrain those subsequent choices.
To continue: browse the shape PLPs at round bathroom mirrors, oval & pill bathroom mirrors, or rectangular & arched bathroom mirrors. For the finish decision and shape-finish coordination, see black framed bathroom mirrors or the shape-finish-feature coordination guide. For the wider decision sequence, read the complete bathroom mirrors buying guide.
Worked sizing examples
Four common UK bathroom situations with the sizing decisions made explicit:
- Standard family bathroom (600mm wall-hung vanity, 1.7m wall, contemporary). Rectangular mirror at 450mm wide (75% of vanity), centred on the vanity (not the wall). Mounted with bottom edge 150mm above the basin rim; centre at 1600mm above the floor. The mirror sits in deliberate proportion to the vanity and leaves wall space either side, reading as restrained.
- Cloakroom downstairs WC (450mm corner vanity, 1.2m wall, tight space). Round mirror at 320mm diameter (71% of vanity), centred on the vanity. Mounted with bottom edge 100mm above the basin rim. Round handles the tight space better than rectangular at this scale, and the smaller proportion suits the constrained room.
- Master ensuite double-basin (1200mm vanity with two basins, 1.4m wall). Two separate round mirrors at 500mm diameter, one above each basin position, centred on each basin (not on the vanity centre). Mounted at matching heights for visual symmetry; the two-mirror arrangement reads more deliberate than one wide mirror spanning both basins.
- Larger family bathroom (800mm vanity, 1.8m wall, room for a feature piece). Arched mirror at 600mm wide (75% of vanity), the arched top adding character without compromising the proportion rule. Centred on the vanity. The wider proportional room allows the slightly more characterful shape; in smaller rooms, plain rectangular would be safer.
Sizes & shapes FAQs
My partner thinks the mirror is too small for our vanity but I think it looks right. Who's right?
Probably you, if the mirror sits between 70% and 80% of the vanity width. Most non-expert eyes mistake correctly-proportioned mirrors for being too small because we're conditioned by oversized hotel mirrors and feature-bathroom imagery. The correct proportion looks restrained because it is; the alternative (mirrors at 95–100% of vanity width) looks impressive but is genuinely oversized by interior-design standards. Measure your mirror as a percentage of your vanity; if it's in the 70–80% range, the proportion is right.
The bathroom designer suggested 800mm but my vanity is only 700mm wide. Should I push back?
Yes, gently. An 800mm mirror over a 700mm vanity sits at 114% of the vanity width, which is meaningfully oversized. The mirror would extend beyond the vanity on either side, and the visual proportion would be wrong. The correct size for a 700mm vanity is 490–560mm rectangular or 450–500mm round. Designers sometimes default to standard sizes (600mm, 800mm, 1000mm) regardless of vanity match; pushing back on the actual proportion is reasonable.
My builder said to centre the mirror in the middle of the wall, not over the vanity. Is that right?
No, centre on the vanity. The mirror's role is functional (reflection at the basin) and aesthetic (matched to the vanity below). Centring on the wall rather than the vanity makes the mirror look orphaned and disconnected from the vanity it's supposed to serve. The exception is feature bathrooms with no fitted vanity (where the basin is freestanding or wall-hung and the wall behind is the design surface); in that case, wall-centre might be right. For standard fitted vanity installs, always centre on the vanity.
My mum thinks all the bathroom mirrors I'm looking at are 'too modern'. Can I get traditional in a modern shape?
Yes. Round mirrors aren't intrinsically modern; they were genuinely common in Victorian and Edwardian bathroom design before becoming uncommon for most of the 20th century. A round mirror in a brushed brass or polished chrome frame reads as period-appropriate, especially paired with traditional taps and tile. The 'too modern' read usually comes from frameless or matte black framed versions of round; a brass-framed round mirror sidesteps that perception entirely.
My contractor wants to install the mirror at standard height (1500mm centre) but I'm 1900mm tall. Should I overrule?
Yes, mount the mirror to your height. Standard heights are for average users; tall users see their face in the upper portion of a standard-mounted mirror or have to bend slightly to centre their face. For a 1900mm user, mirror centre at 1650–1700mm works better. Contractors default to standard because most jobs don't require customisation; flag your height before install and the work is the same complexity at the customised height.
With size and shape decided, browse the relevant shape PLP via the links above, or continue to the bathroom mirrors hub for the wider category view.
Plumbworld has supplied UK bathroom mirrors since 1999, with a 4.8/5 rating from over 60,000 Trustpilot reviews, free UK delivery, a price match promise, and 365-day returns. Getting the size and shape right is a low-risk decision to commit to.
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