Find the perfect mirror dimensions for your bathroom vanity
Founder & CEO, Toolraxy
Faiq Ur Rahman is a web designer, digital product developer, and founder of Toolraxy, a growing platform of web-based calculators and utility tools. He specializes in building structured, user-friendly tools focused on health, finance, productivity, and everyday problem-solving.
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A mirror that’s too wide crowds the wall. One that’s too small looks like an afterthought. This calculator solves the sizing question with numbers instead of guesswork. It reserves clearance for the faucet, keeps the mirror top within reach of the average eye line, and stops the glass short of the ceiling so the frame doesn’t press against the cornice. Frameless mirrors can match the vanity width exactly. Framed mirrors lose ground to their own border. You can switch between metric and imperial at any point, and the values convert in place. Useful before you buy, and useful when you’re standing in the shop trying to remember what your wall looks like.
Pick Metric or Imperial from the toggle at the top.
Measure your vanity width and enter it.
Add the countertop height, measured from the floor.
Add the ceiling height, also from the floor.
Choose single sink or double sink to set the badge and context.
Pick a frame style. Frameless keeps the widest glass.
Pick a height style. Compact, standard, tall, or floor-to-ceiling.
Select the mirror shape you want.
Read the recommended size in the hero panel.
The result updates as you type. No button press needed.
Three rules drive the recommendation.
Formula: Mirror width = vanity width − (2 × frame per side)
Formula: Mirror bottom = countertop height + 18 cm faucet clearance
Formula: Mirror top ≤ ceiling height − 20 cm ceiling clearance
Frame per side depends on the style you pick. Frameless adds nothing. Thin frames take 1.5 cm on each side. Thick frames take 3 cm. Ornate frames take 4.5 cm. Mirror width is clamped between 40 cm and 240 cm so the result never goes to zero or beyond wall-mounted sanity.
Height styles set the target range. Compact aims for 60–80 cm. Standard targets 75–100 cm. Tall pushes to 90–120 cm. The floor-to-ceiling option stretches the mirror from 140 cm up to whatever room the ceiling clearance allows. Available height is ceiling height minus 20 cm minus the bottom mount. The tool picks the largest height within the style’s cap that fits that space.
Every vertical measurement runs from the floor. The tool assumes an eye level of 165 cm for its top-of-mirror reference, which matches the average adult standing height.
Validation catches a vanity width of zero or less, a countertop at or above the ceiling, and blank fields. Invalid combinations trigger an error message instead of a number.
A master bathroom has a 150 cm double vanity, a 90 cm countertop, and a 270 cm ceiling. The owner wants a thick-framed, tall rectangular mirror.
Frame per side: 3 cm
Mirror width: 150 − (2 × 3) = 144 cm
Mirror bottom: 90 + 18 = 108 cm
Available height: 270 − 20 − 108 = 142 cm
Tall style cap: 120 cm
Mirror height: min(142, 120) = 120 cm
Mirror top: 108 + 120 = 228 cm
Ceiling clearance: 270 − 228 = 42 cm
Mirror area: 144 × 120 = 17,280 cm², or 1.73 m²
Aspect ratio: 144 ÷ 120 = 1.20, which lands in the “Landscape” band
The badge reads “Double Vanity Mirror.”
If the owner swapped to a frameless mirror, the width would jump to 150 cm and the area to 1.80 m². Frameless buys back 6 cm of glass across the whole width. For a compact height style instead, the height would drop to 80 cm and the top would sit at 188 cm, leaving 82 cm of clear wall above.
Aim for 90 to 100 percent of the vanity width. On a 100 cm vanity, that means a mirror 90 to 100 cm wide. Frameless mirrors can match the vanity exactly. Framed mirrors lose 2 to 4 cm per side to the frame. Height usually falls between 75 and 100 cm.
The bottom edge sits 18 to 20 cm above the countertop. The top edge should land near the tallest user’s eye level, usually around 165 to 175 cm from the floor. Leave at least 20 cm between the mirror top and the ceiling.
A 180 cm double vanity supports a single 170 to 180 cm frameless mirror or two 75 cm framed mirrors with 20 cm between them. Under 140 cm, two separate mirrors read better than one wide pane. The calculator’s double-sink mode handles this.
Eighteen centimetres from countertop to mirror bottom works for most deck-mounted faucets. Vessel sinks need 25 cm. Wall-mounted faucets can sit closer, around 12 cm, because the spout doesn’t rise from the counter.
Measure the vanity width at the countertop, the countertop height from the floor, and the ceiling height from the floor. Check for sconces, outlets, and towel rings on the wall. A tape measure and a level are the only tools you need.
A powder room with a 45 to 60 cm vanity handles a round or rectangular mirror 40 to 60 cm across. Vertical mirrors make small bathrooms feel taller. Avoid wide landscape mirrors in narrow rooms.
Rectangles suit double vanities and modern bathrooms. Round and oval mirrors work well over single sinks and in powder rooms. Arched mirrors split the difference and read traditional without feeling heavy.
Yes. A nearly wall-to-wall mirror makes the room feel built-in and larger. A smaller mirror lets tile patterns show. Frameless mirrors disappear into the wall. Thick frames add visual weight. Match the mirror to the room’s proportions, not just its style.
Frameless mirrors use the full vanity width because there’s no border eating glass. Framed mirrors lose 2 to 4 cm per side. Thin frames cost less glass than thick or ornate ones. Frameless reads modern. Framed reads traditional or transitional.
Hire a pro for mirrors over 15 kg, mirrors larger than 90 cm in any dimension, or when you’re unsure about studs. Large mirrors are heavy and fragile. A professional install costs £40 to £100, which is cheap compared to replacing broken glass.
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