Getting the right 20-inch cabinet starts before you order, with one accurate number. The trick is knowing that a “20-inch wide cabinet” means the full outside width of the box, not the door or the opening inside. Whether you’re measuring an existing space or planning a new one, this walk-through covers the essentials for a perfect fit.
What Does “20-Inch Wide” Actually Mean?
Cabinet width is always the outside measurement, from the left outer edge to the right outer edge. Door width, handle width, or the clear opening inside are never used to determine the cabinet size. So a 20-inch wide cabinet is the total box width you’re working with.
Standard cabinet references show typical base cabinet widths in 3-inch increments, like 12, 15, 18, 21, 24, and 30 inches. A 20-inch width isn’t a standard stock size in many guides, which means it might be a custom product or from a specific vendor. Always confirm the exact outside width on the product’s spec sheet before measuring your space.
To see a range of options that meet this size, check out our roundup of tested 20-inch wide cabinet picks to find one that fits your plans.
Measuring the Cabinet Itself
For a single box, the process is simple. Use a tape measure and follow these steps:
- Place the tape at the far left outer edge of the cabinet’s body, not the door or trim.
- Pull the tape straight across to the far right outer edge, keeping it level.
- Record the measurement in inches. This figure is the cabinet’s true width.
For example, a typical 20-inch wall cabinet is listed at 20″ wide, 24″ high, and 12″ deep without doors (12 3/4″ with doors). A base cabinet of the same width is typically 20″ wide, 35″ high including legs, and 24″ deep without doors (24 3/4″ with doors). Don’t assume these dimensions; always check the specs for your exact model.
Measuring the Opening or Wall Space
When fitting a cabinet into a specific spot, the opening is what matters most. To get it right:
- Measure the full wall length corner-to-corner, then note any windows, doors, or outlets that affect the usable space.
- For the opening width, measure from wall to wall at the top, middle, and bottom. Walls are rarely perfectly straight, so take multiple points.
- Account for trim, door casing, hinges, and any appliance rough-ins before you order.
Here’s a quick summary to keep your numbers straight:
| Measurement Point | What To Do | Why It Matters |
|---|---|---|
| Cabinet Box Width | Measure from outer edge to outer edge. | This is the true 20″ width for fit. |
| Opening at Top | Measure wall-to-wall near the top. | Accounts for walls that lean inward. |
| Opening at Middle | Measure wall-to-wall at the center height. | Catches the most common bow in drywall. |
| Opening at Bottom | Measure wall-to-wall near the floor. | Checks for baseboard or floor variance. |
| Narrowest Point | Use the smallest of all width readings. | This is the number your cabinet must fit. |
Avoiding Common Fit Mistakes
Most fit problems come from a few predictable errors. Measure each cabinet individually, and never rely on a neighboring unit’s dimensions, because they can vary. Also remember to plan for obstructions like outlets and plumbing before you order.
Even a slightly oversized cabinet may not fit if the wall is out of plumb. Using fillers to adjust for level and plumb issues is a smart practice, not a sign of failure. For the best final result, account for these factors in your plan from the start.
References & Sources
- Cabinet Corp. “Standard Cabinet Sizes and Dimensions Guide.” Details common widths and depth measurements for base and wall cabinets.
- Lowe’s. “Kitchen Cabinet Measurement Guide.” Provides best practices for measuring wall length, obstructions, and installation fit.
