Measure the vanity, the faucet and the light above the mirror. You get the medicine cabinet size to buy, how high to hang it, and, recessed, the hole it needs and how many studs it cuts.
Medicine cabinet
A 24″ × 30″ cabinet, its bottom 47″ upno wider than the 30″ vanity, 3″ over the faucet · recessed: a 23⅝″ × 28¼″ hole, 1 stud cut and framed
Quick answer: a medicine cabinet should be no wider than the vanity and fit between the faucet and the light (Kohler), with its bottom at least 3″ above the faucet. Over a 30″ vanity that is a 24″ × 30″ cabinet. Recessed, it needs Kohler’s cutout, here 23⅝″ × 28¼″ × 3 11⁄16″ deep. With studs 16″ apart only 14½″ is clear between two of them, so every Kohler Verdera means cutting at least one stud and framing the opening.
How to use the medicine cabinet size calculator
- Measure the vanity’s width and the top of the faucet from the floor (or the backsplash, if it is higher).
- Measure the bottom of the light above the mirror, if there is one. It caps the cabinet’s height.
- Pick recessed or on the wall, and for recessed, whether the studs are 16″ or 24″ apart (find two with a stud finder and measure between their centres).
- Read the cabinet, how high its bottom goes, and for a recessed one the hole and how many studs it cuts.
The rules behind the numbers
No wider than the vanity
Kohler: “your medicine cabinet should be narrower or the same width as the vanity. To determine the height, measure the distance between your lights and faucet. Choose a medicine cabinet size that provides clearance above the faucet and below the lights.” The calculator picks the widest cabinet Kohler sells that fits, then the tallest.
3″ over the faucet
Every Kohler Verdera spec sheet: “Install the cabinet a minimum of 3″ (76 mm) above any obstructions (such as a faucet).” That sets the cabinet’s bottom; its height sets the top.
The hole and the studs
A recessed cabinet needs the “cutout” printed on its spec sheet. House walls have studs 16″ or 24″ apart, centre to centre, and a 2×4 is 1½″ thick, so 14½″ or 22½″ is clear between two studs. A wider hole cuts a stud, and Kohler says “the wall cavity must be framed and the cabinet must be secured to studs”; pipes, wires or a load-bearing wall mean a professional first. The cutout is 3 11⁄16″ deep; a 2×4 wall behind ½″ of drywall gives 4″.
Medicine cabinet sizes and the hole each needs (Kohler Verdera)
| Cabinet | Cutout (recessed) | Studs cut, 16″ apart | Studs cut, 24″ apart |
|---|---|---|---|
| 15″ × 30″ | 14⅝″ × 28¼″ | 1 | 0 |
| 20″ × 26″ | 19⅝″ × 24¼″ | 1 | 0 |
| 20″ × 30″ | 19⅝″ × 28¼″ | 1 | 0 |
| 24″ × 30″ | 23⅝″ × 28¼″ | 1 | 1 |
| 34″ × 30″ | 33⅝″ × 28¼″ | 2 | 1 |
| 40″ × 30″ | 39⅝″ × 28¼″ | 2 | 1 |
Every cutout is 3 11⁄16″ deep. Other brands print their own cutout on their spec sheets: check it before you cut, since even the 15″ Verdera needs ⅛″ more than the 14½″ between studs 16″ apart.
Three worked examples
A 30″ vanity, the faucet’s top 44″ up, studs 16″ apart. A 24″ × 30″ cabinet, its bottom at 47″ and top at 77″. Recessed, the 23⅝″ hole cuts 1 stud.
A 24″ vanity under a light whose bottom is 72″ up. Only 27″ is left between 3″ over the faucet and the light, so the 20″ × 26″ cabinet: its top at 71″, 1″ under the light.
A 48″ double vanity, studs 24″ apart. The 40″ × 30″ three-door cabinet, a 39⅝″ hole that cuts 1 stud.
Common medicine cabinet mistakes
- Buying by the box size. Recessed, the cutout is what the wall must give, and it is on the spec sheet, not the box front.
- Assuming it fits between the studs. 14½″ is all a 16″ stud bay gives.
- Hanging it on the faucet. Kohler asks for at least 3″ of clearance so the door opens over the spout.
- A cabinet wider than the vanity. Kohler: the same width or narrower.
- Cutting before looking. A bathroom wall often holds the drain vent, supply pipes or wiring.
Want a plain mirror instead? The free vanity height and mirror size calculator sizes it. The wall sconce height calculator places the lights beside it, and the free 2D room planner lays out the bathroom.
Size a mirrorRead next
Medicine cabinet questions
What is a standard medicine cabinet size?
Kohler’s Verdera line is 15″, 20″, 24″, 34″ and 40″ wide, most of them 30″ tall (one 20″ × 26″). Choose one no wider than the vanity that fits between the faucet and the light.
What medicine cabinet size for my vanity?
The same width as the vanity or narrower (Kohler). Over a 24″ vanity, a 20″ or 24″ cabinet; over 30″, a 24″ one; over a 48″ double vanity, a 40″ three-door cabinet.
What is the medicine cabinet height?
Its bottom at least 3″ above the faucet (Kohler), and its top below the light. With a 44″ faucet top, a 30″ cabinet runs from 47″ to 77″.
What are recessed medicine cabinet dimensions?
The cabinet’s front is its size; the hole is its “cutout”. Kohler’s 24″ × 30″ Verdera needs 23⅝″ × 28¼″, 3 11⁄16″ deep: wider than the 14½″ between studs 16″ apart, so one stud is cut and the opening framed.
Will a medicine cabinet fit between studs?
Only if its cutout is no more than 14½″ wide (studs 16″ apart) or 22½″ (24″ apart). Even Kohler’s 15″ Verdera needs 14⅝″.
What is a big medicine cabinet?
34″ and 40″ wide, with two or three doors, for a double vanity. Recessed, a 40″ one cuts two studs spaced 16″ apart.