Glass dimensions
For a custom frameless mirror, width and height normally describe the finished mirror glass itself.
Before selecting a size
Three Measurements Can Describe Different Things
A mirror listing may refer to the glass itself, the reflective opening or the completed outside dimensions. Confirming which measurement is being used prevents a framed mirror, bevelled design or mounting system from exceeding the available wall space.
Mirror opening
For a framed mirror, a requested glass or opening size does not necessarily equal the final outside frame dimensions.
Finished product size
Ready-made mirrors are generally planned by their complete outside dimensions, including the frame and other factory-produced details.
Browse by shape and size
Popular Mirror Dimension Guides
Every size page leads with exact custom fabrication, then identifies relevant ready-made products at or close to that dimension without describing nearby alternatives as exact matches.
Round Mirrors
All round mirrors →Oval Mirrors
All oval mirrors →Rectangle Mirrors
All rectangle mirrors →Arch Mirrors
All arch mirrors →Browse custom frameless possibilities and completed designer mirrors in this shape.
Square Mirrors
All square mirrors →Irregular Mirrors
All irregular mirrors →Browse custom frameless possibilities and completed designer mirrors in this shape.
Octagon Mirrors
All octagon mirrors →Browse custom frameless possibilities and completed designer mirrors in this shape.
Measurement checklist
Measure the Installation, Not Only the Empty Wall
A useful starting measurement includes every feature that affects the mirror, along with the route used to deliver and position it.
Vanity and fixtures
Record the cabinet, sink, faucet, backsplash, sconces, ceiling light, outlets and switches.
Wall and surrounding finishes
Identify trim, tile edges, sloped ceilings, shelving, doors and any change in wall depth or material.
Orientation and reflection
Decide whether the mirror should be portrait, landscape or symmetrical and what users need to see from normal viewing positions.
Access and mounting
Measure doors, stairs, elevators, corners and ceiling clearances, then consider the wall construction and final mirror weight.
Exact size or finished design
Custom Fabrication and Ready-Made Mirrors Use Dimensions Differently
Choose custom fabrication when the dimensions and installation lead the project. Choose a ready-made mirror when its completed shape, frame, bevel or decorative finish is the priority.
Mirror Sizes & Shapes FAQ
Can Centennial make a mirror in a size not listed in this guide?
Yes. The listed dimensions are useful starting points, not the limits of custom fabrication. Final size, shape, edge and installation requirements must be confirmed for the project.
Does a 30 × 40 framed mirror measure 30 × 40 outside?
Not necessarily. The measurement may describe the glass or mirror opening, while the selected frame adds to the completed outside dimensions. Confirm which measurement must remain 30 × 40 inches.
Can round and oval custom mirrors receive Centennial wood or metal frames?
Centennial’s custom framing service is for rectangular and square mirrors. Custom round and oval mirrors are frameless; framed curved designs are selected from the ready-made collection.
How are nearby ready-made sizes shown?
The size pages separate exact catalogue matches from nearby alternatives and display the actual dimensions of each ready-made mirror.
Bring your dimensions
Visit our showroom to compare sizes and finishes
See ready-made mirror proportions in person or bring the wall measurements and project photos to discuss custom fabrication, framing and installation.