Wall cabinet dimensions: height, depth, widths and how high to hang them

Published October 1, 2026 by Design Master Solutions LLC

Wall cabinets, also called uppers, are where a layout meets the ceiling. Their standard sizes are few: 12 inches deep, 30, 36 or 42 inches tall, and widths from 9 to 36 inches in 3-inch steps. What makes them work is the height they hang at, and that is one number: 54 inches from the floor to the bottom of the box.

Nominal sizes; always check the manufacturer's spec book, especially for ceiling height and crown molding.

Standard wall cabinet sizes

In a wall cabinet SKU the digits are width then height: W3030 is 30 wide and 30 tall, W1842 is 18 wide and 42 tall. The SKU codes guide covers the rest of the prefixes.

The 18-inch gap and the 54-inch line

The usual gap between the countertop and the bottom of the wall cabinets is 18 inches. On a 36-inch counter that puts the bottom of every upper at 54 inches from the floor. It leaves room for small appliances on the counter and keeps the bottom shelf in reach.

From there the ceiling picks the cabinet height:

• 8-foot ceiling (96 inches): 42-inch uppers reach the ceiling. 36-inch uppers leave 6 inches, often closed with crown molding. 30-inch uppers leave a foot of open soffit.
• 9-foot ceiling (108 inches): even 42-inch uppers leave 12 inches above. Some lines sell stacked uppers or taller sizes for this; check what yours offers.

Measure the ceiling at several points before you order. An old house can lose half an inch across a wall, and a 42-inch upper with crown has no room for that.

Depth: 12 inches

Wall cabinets are 12 inches deep as a box, half the depth of a base. That keeps the counter usable under them and your head clear of the doors. The depth matters at corners: a 12-inch upper that runs into a corner takes the first 12 inches of the next wall, so the run on that wall starts 12 inches out.

Over the refrigerator

Above a refrigerator, a full-height upper would sit too low. Short wall cabinets go there instead: W3015 or W3615 (15 tall), or W3624 (24 tall), sized to the refrigerator width. Pick the height from the refrigerator's real height plus the clearance its maker asks for at the top, then check that the top of the cabinet lines up with the other uppers. Some lines also sell a deeper over-refrigerator cabinet so it can be reached over a deep refrigerator; check the spec book. A tall end panel (REP2496) often closes the side of the refrigerator.

Over the range: hood or microwave

Over the cooktop the wall cabinets stop and leave a space for a hood or an over-the-range microwave, usually 30 or 36 inches wide to match the range. A short wall cabinet usually sits above the microwave or hood. The clearance between the cooktop and the hood or microwave comes from that appliance's installation guide, not from the cabinet catalog; read it before you choose the cabinet above.

How Cabinet Project uses these sizes

The "Starter sizes" line every new company gets has the full grid of W0930 to W3642 in 30, 36 and 42, plus W3015, W3615, W3624 and DCW2430, at list price 0 until you import your price list. In the layout editor you choose 30, 36 or 42 for the wall band, and each upper hangs at 54 inches from the floor unless your catalog gives another height. A hood or microwave is placed as an appliance in the wall band at 30 or 36 inches wide; it takes space like a box and is never priced. A window blocks the wall band only where its height reaches 54 inches.

Wall boxes add up to wall linear feet, counted apart from base, because hanging uppers and setting bases are different work. See the full chart in kitchen cabinet sizes, the base side in base cabinet dimensions, and count a wall with the linear foot calculator.