Bathroom mirror sizing guide: how do I size a mirror for my vanity?
Quick action plan
This bathroom mirror sizing guide gives you three measurement numbers to collect before you call for a quote: the vanity width, the available wall width above the vanity, and the vertical distances from floor to vanity top and to any lights or fixtures. Have a tape measure, level, pencil, masking tape, and a helper. Decide first whether you want a single mirror or individual mirrors for each sink, then follow the numbered steps below or book a free on-site measurement with a professional at OZ Shower Doors.
Tools, terms and recommended tolerances
Before you measure, gather these tools and understand the terms used in this guide.
- Tools: 5 m tape measure, 24-inch level or laser level, pencil, masking tape, step stool, helper, and a phone to photograph and share markings.
- Key terms: vanity width is the finished cabinet edge to edge. Centre line is the midpoint of the sink or vanity. Backsplash is the short wall area directly behind the vanity top. Clearance is the space left between mirror edges and nearby fixtures.
- Recommended tolerances: allow 12 to 25 mm (1/2 to 1 inch) gap from mirror edge to nearest fixture or tile trim, and plan for at least 25 mm clearance above a backsplash. Treat these as practical guidelines, not mandatory rules.
Step-by-step measurements: single vanity
Follow these seven steps and note each measurement so you can give accurate details to a fabricator.
-
Measure vanity width
Measure the full finished width of the vanity cabinet from outer edge to outer edge. Record this on paper, and also note if the countertop overhang extends beyond the cabinet.
-
Locate the centre line
Find and mark the centre line of the sink or vanity top. For single-sink vanities this is usually the horizontal axis you will centre the mirror to.
-
Measure available wall width
Measure the clear wall space above the vanity from the nearest obstruction on the left to the nearest obstruction on the right, such as wall returns, towel bars, or vertical trim. If you plan a mirror that nearly spans the vanity, leave the recommended tolerance gaps noted above.
-
Note nearby fixtures and switches
Record locations of light fixtures, outlet boxes, and plumbing vents. Measure from the centre line to each fixture so the fabricator can plan cutouts or avoid hardware conflicts.
-
Measure vertical heights
Measure from the finished floor to the vanity top, and from the vanity top to the lowest edge of any overhead light. These two numbers determine the mirror lower edge position and the maximum mirror height without hitting fixtures.
-
Decide mirror width relative to the vanity
A common recommendation is to make the mirror between 60 and 90 percent of vanity width, depending on style and wall space. For a framed mirror, subtract the frame width from the final visible glass size. Industry sizing guides recommend leaving small edge gaps to avoid mirror-to-fixture contact.
-
Mark the final outline on the wall
Use masking tape to mark the proposed mirror edges and height on the wall. Step back and check sight lines at eye height for users of different heights. Photograph the taped layout to share with your fabricator or installer.
Step-by-step measurements: double vanities and separated sinks
Double vanities need a few extra decisions. Use this process to choose a single continuous mirror or two separate mirrors.
-
Measure total vanity width and each sink centre
Record the full cabinet width and the centre point for each sink. For symmetry, mirrors are usually centred to each sink when using two mirrors.
-
Decide single mirror or two mirrors
If you want uniform reflection and shared LED lighting, a continuous mirror across most of the vanity creates a unified look. If individual task lighting and separate framing are preferred, choose two mirrors sized to each sink. Consider whether wall fixtures or outlets sit between sinks; these will affect the practicality of one continuous mirror.
-
Set spacing and edge clearances
If you choose two mirrors, leave 50 to 150 mm (2 to 6 inches) between them for visual separation and shared lighting. If you use a single mirror, centre it across the entire vanity width while maintaining the edge gap tolerance to trim and walls described above.
-
Mark and check lighting
Mask out the mirror outlines and check how overhead or sconce lighting will reflect. For double mirrors, make sure each sink has adequate light without glare from adjacent fixtures.
Placement rules: height, vertical clearance and alignment
Use these placement rules to set comfortable viewing height and to avoid conflicts with lighting or plumbing.
- Lower mirror edge: commonly 100 to 150 mm (4 to 6 inches) above the vanity top to clear backsplash and allow users to see full face and shoulders.
- Mirror height: choose a top edge that keeps the reflected image comfortable for the tallest regular users, while remaining below overhead fixtures. Practical placement checks will confirm lighting and clearance.
- Eye-level check: have household members stand at the vanity and mark eye height on the taped outline. If more than one regular user is present, centre the mirror vertically between typical eye heights or favour the primary daily user.
- Aligning with light fixtures: for framed mirrors align the frame bottom with the lower edge of fixtures when possible. For frameless or LED mirrors, aim to keep integrated lighting unobstructed and centred.
Shape, style and lighting: choose what matches scale and function
Shape changes perception. Rectangular mirrors read as wider and more formal. Vertical or oval mirrors emphasise height and soften hard bathroom lines. Frameless mirrors make a space feel larger, while framed mirrors add contrast and a finished look.
If you prefer a softer silhouette, consider an oval mirror as an option. OZ Shower Doors manufactures and installs LED, framed, and frameless mirrors, so you can specify integrated lighting or a polished-edge frameless design when you request a custom quote from OZ Shower Doors.
Decision criteria for lighting: choose integrated LED if you want even shadow-free lighting for grooming. Choose overhead or sconce lighting when you prefer classic fixtures and a framed mirror.
Mounting and hardware: what to plan for different walls
Common mounting systems include z-clips, French cleats, and bracket anchors. The wall type determines anchor choice.
- Drywall: use anchors rated for the mirror weight, or mount into studs for heavy mirrors.
- Tile: drill slowly with a carbide or diamond bit and use proper anchors to avoid cracking tiles. If your mirror requires backing electrical for LEDs, plan the outlet box location in advance.
- Concrete or cement block: use masonry anchors and a hammer drill. For large mirrors the installer may recommend blocking or a framed substrate.
When drilling tile or mounting heavy glass, hiring a professional installer reduces the risk of damage or incorrect fasteners. OZ Shower Doors’ in-house installation service handles wall assessment, blocking, and secure mounting as part of their end-to-end process.
Common mistakes to avoid and a short troubleshooting checklist
These errors are frequent but easy to prevent.
- Measuring to the wrong edge. Always measure finished cabinet edges, not countertop overhangs.
- Forgetting fixture clearance. Mark light and switch locations before finalising mirror width.
- Not checking vertical sight lines. Tape the outline and step back to check reflection at different heights.
Troubleshooting checklist before you order:
- Confirm vanity width, wall width, and heights in writing and with photos.
- Verify the mirrored area will not contact fixtures or trim, using the tolerances above.
- If you plan LED or an electrical cutout, confirm outlet location and provide it to the fabricator.
If something is wrong after installation, document the issue with photos, note the mounting details, and contact your fabricator or installer to arrange inspection. Local reviews indicate installers who follow up quickly improve outcomes, so check service commitments when you request a quote.
What to expect when ordering a custom mirror in Edmonton
OZ Shower Doors offers an end-to-end workflow: consultation, free on-site measurement and custom design, in-house fabrication, scheduled professional installation, and follow-up. The company highlights local manufacturing and reports more than 2,700 projects and over 280 monthly deliveries, which underlines local capacity for custom jobs at OZ Shower Doors.
When you book, expect the installer to ask for your taped outline photos, measurement notes, and lighting preferences. Ask the fabricator about available hardware finishes, LED options, expected lead time, and warranty details during the quote conversation.
Next steps and printable measurement template
Follow the numbered measurement steps above and either attach photos and measurements to an online quote, or book a free on-site measurement with a local fabricator. When booking, have these items ready:
- Photos of the vanity wall with masking tape outlines
- Vanity width and sink centre measurements
- Distances from floor to vanity top and from vanity top to any overhead fixtures
- Your preferred mirror style: framed, frameless, LED, oval, or rectangular
Before you book, check the design choices you want to confirm at the quote: frame finish, visible glass edge, LED colour temperature, and whether the mirror will be one continuous panel or split into two. Use the oval mirror example on the OZ Shower Doors site when you need a shape reference: oval mirror.
Frequently asked questions
How wide should a bathroom mirror be for my vanity?
Choose a mirror between 60 and 90 percent of the vanity width for balanced proportions, or centre a mirror to the sink if you prefer a smaller framed look. Leave small edge gaps to avoid fixtures and trim; industry placement guides offer practical examples.
How high should I hang a bathroom mirror above the vanity?
Common practice places the lower mirror edge 100 to 150 mm above the vanity top, which clears backsplashes and gives useful viewing height. Adjust vertically for the tallest or shortest regular users and for overhead fixtures using the tape outline check described above.
Can I add LED lighting to a custom mirror and still match the correct size?
Yes. Plan for the LED module and any rear housing when you provide measurements. Specify integrated lighting to your fabricator so they account for electrical cutouts and clearances during fabrication. OZ Shower Doors supplies and installs LED and framed or frameless mirrors as part of their custom service.
Can a custom mirror be installed on tile or concrete walls?
Yes. Tile requires careful drilling with the correct bit to avoid cracking and masonry anchors are used for concrete. For heavy or large mirrors installers often recommend blocking or mounting into studs. When in doubt hire a professional installer for assessment and secure mounting.
What happens during an on-site measurement and quote from OZ Shower Doors?
An OZ visit includes a site assessment, detailed measurements, material and finish options, and a written quote. OZ follows an in-house process from consultation to installation and notes local fabrication capacity in Edmonton.
Ready to make a decision and book a free on-site measurement with OZ Shower Doors?
