Key Takeaways
- Always measure your vanity width first - your mirror should be slightly narrower than the vanity unit beneath it
- Record measurements in both centimetres and millimetres to avoid costly ordering errors
- Account for clearance space around light switches, power points, and cabinetry before finalising your size
- Height placement matters as much as width - measure for eye-level centring, not just for fit
- Wall type (plaster, tile, brick) affects your installation approach, so check this before you order
- Having your measurements ready makes it much easier to filter through bathroom mirror collections and find the right fit
Buying a new bathroom mirror sounds simple enough until you actually stand in front of the wall with a tape measure, trying to remember whether you wrote that number down correctly. It happens more often than you might think. A mirror arrives, looks brilliant out of the box, and then either sits too close to the towel rail or ends up awkwardly small above a wide double vanity.
Getting your measurements right before you buy is genuinely the most important step in the whole process - more important than the style you choose, more important than the finish. And the good news is that it really does not take long if you know what you are looking for.
At LED Mirror World, we see this come up regularly with customers who are mid-renovation or upgrading an outdated bathroom. So we have put together this guide to walk you through every step, clearly and practically, so you can shop with confidence.
Step 1: Understand the Space You Are Working With
Before you even pick up a tape measure, take a few minutes to look at the wall properly. Note the following:
- Where is your vanity positioned, and how wide is it?
- Are there any wall-mounted fixtures nearby (towel rails, light switches, shaver points, cabinetry)?
- Is there natural light coming from a window on either side?
- What is the wall surface - plaster, painted brick, or tiles?
These factors will all influence the size and shape of mirror that actually works in the space. A large statement mirror might look perfect on paper but feel cramped if a towel rail sits 10 cm to the right. Knowing your wall before measuring saves you from making decisions you will have to undo later.
Step 2: Measure the Width of Your Vanity
This is your starting point. The width of your vanity unit (the bench or cabinet beneath the mirror) is the most reliable guide for your mirror's width.
Use a steel tape measure - not a fabric one, which can stretch slightly and give you inaccurate readings. Measure from one outer edge of your vanity to the other, and write the number down in millimetres. Precision here matters.
General width guidelines:
- Single vanity (600 mm - 900 mm wide): A mirror between 500 mm and 800 mm wide typically looks well-proportioned
- Standard vanity (900 mm - 1200 mm wide): A mirror between 750 mm and 1100 mm wide suits this range well
- Double vanity (1200 mm - 1800 mm wide): A mirror between 1000 mm and 1700 mm wide, or two mirrors side by side, both work
The key principle is that your mirror should sit within the vanity width, not extend beyond it. Going slightly narrower than the vanity - by around 50 mm to 100 mm on either side - tends to look intentional and clean. Going wider can make the space feel unbalanced, particularly if there are walls or cabinetry directly adjacent.
If you are browsing our rectangle LED bathroom mirrors, filtering by width first will narrow your options quickly and meaningfully.
Step 3: Measure the Available Wall Height
Once you have your width sorted, measure the usable wall height above your vanity. This is not just the ceiling height - it is the vertical space between the top of your vanity (or the backsplash, if there is one) and any overhead obstruction like a ceiling-mounted exhaust fan, a light fitting, or the bottom of a wall cabinet.
Measure from the top of the vanity or backsplash straight up to the lowest fixed point above it. Write this down.
For most Australian bathrooms, a mirror height between 600 mm and 900 mm works well. Very tall mirrors (1000 mm or more) can be stunning in bathrooms with generous ceiling heights, but they need the vertical clearance to justify them - and enough wall space that they do not crowd the ceiling.
Step 4: Mark Out Your Clearance Zones
This step is easy to skip, which is exactly why so many people end up with a mirror that technically fits but creates practical problems.
Walk around the wall and identify the following:
Horizontal clearance: How much wall exists between the edge of your vanity and the next fixed element (a door frame, a wall-mounted cabinet, a shaver point)? Your mirror needs to fit comfortably inside this horizontal run, with at least 50 mm clear on each side from any obstacle.
Vertical clearance: If you have overhead lighting or a recessed downlight directly above the vanity, you need to ensure your mirror does not sit so high that it looks crammed beneath it. Aim for at least 100 mm between the top of the mirror and the nearest overhead fitting.
Side clearance for lit mirrors: If you are installing an LED mirror with backlit or frontlit illumination, the glow will extend slightly beyond the mirror edge. Allow a little extra breathing room - at least 80 mm from any adjacent wall, cabinet, or door frame - so the lighting can do its job without being cut off.
Step 5: Determine Ideal Mirror Height Placement
Where the mirror sits on the wall is just as important as how large it is. A mirror installed too high will force shorter users to stand on their toes. One installed too low can make a bathroom feel compressed.
The standard approach for a single-height household is to centre the mirror at eye level. Average eye level for an adult standing at a vanity is approximately 1500 mm to 1600 mm from the finished floor. So if your mirror is, say, 700 mm tall, the centre of the mirror should sit at roughly 1550 mm, meaning the bottom edge of the mirror sits at approximately 1200 mm from the floor.
For households with both adults and children using the same bathroom, positioning the bottom edge of the mirror lower - around 900 mm to 1000 mm from the floor - allows better usability for everyone without making the mirror feel cramped.
Mark your intended top and bottom mirror positions on the wall with a pencil. Step back and check how it looks in context. You are essentially previewing the installation before anything is purchased.
Step 6: Check the Wall Type and Identify Studs or Noggins
The surface you are hanging from determines everything about how the mirror is fixed. Most Australian homes have either:
- Plasterboard walls - common in newer builds, these require wall anchors or direct fixing into studs for heavier mirrors
- Tiled walls - require tile drill bits and may involve hollow wall anchors if no stud sits behind the tile
- Brick or masonry walls - require hammer drill bits and masonry plugs
Use a stud finder to locate any timber framing behind the wall surface. For heavier LED mirrors - particularly large rectangular or double-lit options - fixing directly into a stud or noggin will provide the most secure and lasting installation.
Knowing your wall type also helps you plan ahead. If you are ordering a large backlit and front-lighted LED mirror, which can weigh 10 kg or more depending on the size, you will want to know whether your wall can support that weight at the desired position before the mirror arrives.
Step 7: Write Everything Down and Double-Check
Before you close the tape measure and start browsing, write down the following:
- Vanity width (mm)
- Maximum mirror width available (accounting for clearances)
- Maximum mirror height available (accounting for overhead clearances)
- Intended bottom edge height from floor (mm)
- Wall type
- Any electrical points or fixtures in the vicinity
Then measure again. Seriously - measure twice, write it down once. The most common measurement error is transposing a digit or rounding to the nearest 5 cm when the actual available space is more precise than that.
If you are considering a cabinet-style option for added storage, our guide to choosing a bathroom mirror with storage covers depth dimensions and clearance considerations that are slightly different from standard flat mirrors.
What to Do With Your Measurements
Once you have your numbers, you are in a genuinely good position to shop well. You know your maximum width and height. You know where the mirror will sit. You know what your wall can support.
From here, it is worth thinking about shape as well as size. Our post on bathroom mirror shapes and which style suits different spaces is a useful read once the practical dimensions are settled.
If you are drawn toward an illuminated mirror - and many Australian homeowners are, particularly for bathrooms without large windows - knowing your exact measurements means you can filter our full range of LED bathroom mirrors by size and find something that fits your space precisely rather than approximately.
For something that makes a strong visual impact while staying practical, the large dimmable anti-fog backlit LED mirror is popular with customers who have wider vanities and want the mirror to feel like a genuine centrepiece. And once you have confirmed your measurements, our guide on how to install a bathroom mirror safely will take you through the next steps.
Ready to Find Your Mirror?
Taking the time to measure properly means you buy once and buy right. Whether you are planning a full bathroom renovation or simply replacing an outdated mirror, the numbers you gather in these steps will make every subsequent decision easier.
If you have your measurements ready and would like personalised advice on which mirror suits your space, we would love to help. Reach out to our team directly through our contact page and tell us your dimensions - we are happy to point you in the right direction.
Frequently Asked Questions
How wide should a bathroom mirror be compared to the vanity?
A bathroom mirror is typically 50 mm to 100 mm narrower than the vanity on each side. For example, a 900 mm wide vanity pairs well with a mirror between 700 mm and 800 mm wide. This creates a balanced, proportional look without the mirror overhanging the edges of the vanity unit.
What height from the floor should a bathroom mirror be hung?
For most adults, the centre of the mirror should sit at approximately 1500 mm to 1600 mm from the finished floor. If the mirror is 700 mm tall, the bottom edge would sit at around 1200 mm. Adjust slightly lower if children also use the bathroom regularly.
Can a bathroom mirror be the same width as the vanity?
Yes, a mirror can match the vanity width exactly, particularly in contemporary designs where a flush or matched look is intentional. Just ensure there is adequate wall clearance on both sides and no adjacent obstacles like power points or cabinetry.
Do LED mirrors require extra clearance on the wall?
LED mirrors with backlighting or frontlighting produce a visible glow that extends slightly beyond the mirror's edge. It is advisable to allow at least 80 mm of clearance from the nearest wall, door frame, or cabinet so the light effect is not cut off or obscured.
What is the minimum gap needed between a bathroom mirror and the ceiling?
There is no universal rule, but a gap of at least 150 mm to 200 mm between the top of the mirror and the ceiling is generally recommended for visual balance. If overhead lighting or an exhaust fan is present, increase this clearance to at least 100 mm from the nearest fitting.
How do I measure for a mirror if my bathroom wall is tiled?
Measure in the same way - using a steel tape measure from edge to edge of your available space. The tiled surface itself does not change your measurements, but it does affect your installation method. Tiled walls require a tile drill bit and appropriate wall anchors, and it is worth confirming whether studs or noggins sit behind the tiles before choosing a mirror position.
Does the shape of the mirror affect how I measure?
The measuring process is the same for all shapes, but how you apply those measurements varies. For round or oval mirrors, the key measurement is diameter. For arched or irregular shapes, note both the maximum width and the maximum height. Always check the product dimensions listed on the mirror's page and compare them against your available wall space.