Standard cabinet sizes are the same across North America: base cabinets 34½″ tall and 24″ deep, wall cabinets 12″ deep at 30, 36 or 42″ high, tall pantries 84, 90 or 96″, and widths in 3″ steps — 12″ to 36″ for a base, plus 42″. Learn those constants and how to read a code like B18, and a cabinet list stops looking like a foreign language.
Cabinets are not made to order in three-quarter-inch increments; they come in a fixed ladder of sizes, and the whole craft of laying out a kitchen is choosing which rungs add up to your wall. Learn the ladder once and you can plan any kitchen — ours or anyone else’s. It is also where the shop dimensions start if you are cutting the boxes yourself.
Memorise these and most of a kitchen falls into place. They are not our house style — they are the industry standard your appliances, countertops and backsplash tiles are all built around.
| What | Number | Why it is that |
|---|---|---|
| Base cabinet height | 34½″ | Plus a 1½″ countertop = a 36″ work surface |
| Toe kick | 4½″ | Part of that 34½″, so the box face is 30″ |
| Base depth | 24″ | Matches every dishwasher and range on the market |
| Wall cabinet depth | 12″ | Deep enough for dinner plates, shallow enough to work under |
| Wall cabinets start at | 54″ | 19½″ above the base cabinets — the standard 18″ of backsplash above a 36″ counter |
| Countertop overhang | 1½″ | Past the box face, so doors clear and drips fall clear |
Wall cabinets hang from the same 54″ line, so their height sets where the kitchen ends: 30″ tops out at 84″, 36″ at 90″, 42″ at 96″ — exactly an eight-foot ceiling. That is the whole reason 42″ uppers exist.
What they search at midnight “what do kitchen cabinet codes mean” — letters say what it is, digits say how big.
The rule is simple: letters = the family, first two digits = width, next two = height. Where a family has only one possible height — every base cabinet is 34½″ — the height digits are simply left off.
| Code | Reads as | Which means |
|---|---|---|
| B18 | Base, 18″ wide | 34½″ high × 24″ deep — one drawer over one door |
| W3030 | Wall, 30″ wide × 30″ high | 12″ deep, two doors |
| SB36 | Sink base, 36″ wide | False drawer front, two doors, no shelf in the way of the trap |
| DB30-3 | Drawer base, 30″ wide, 3 drawers | 6″ + 12″ + 12″ fronts |
| PC2490 | Pantry cabinet 24″ wide × 90″ high | 24″ deep, floor to near-ceiling |
| B24DD | Base 24″, double doors | DD forces two doors where one is standard |
| B18FD | Base 18″, full door | FD = no top drawer, one full-height door |
| W301224 | Wall 30″ × 12″, 24″ deep | A third pair of digits is depth — this is the over-fridge box |
| BBC36-42 | Blind base corner | A 36″ box that fills 42″ of the wall including its filler |
| MWEP1230 | Wall end panel | Panels invert it: 12″ deep × 30″ high × ¾″ thick |
Once you see it, every list makes sense: Base, Wall, Sink Base, Drawer Base, Pantry Cabinet, Blind Base Corner, Easy Reach. The suffixes are a small vocabulary of their own: DD double doors, FD full door, FDD full double doors, -3 or -2 the number of drawers.
Base cabinets come in 3″ steps from 12″ to 36″, plus 42″ — 12, 15, 18, 21, 24, 27, 30, 33, 36, 42. All of them are 34½″ high and 24″ deep. A cabinet wider than 24″ gets two doors; 24″ and under gets one, unless you ask for the double-door version.
| Family | Widths | What it is |
|---|---|---|
| B## | 12–36, 42 | The default: one 6″ drawer over a door (or two) |
| B##FD | 9–36, 42 | Full-height door, no drawer — the one to use beside a dishwasher |
| DB##-3 | 12–36 (42 via sales) | Three drawers: 6″ + 12″ + 12″ |
| DB##-2 | 30, 33, 36 | Two deep drawers — pots, and nothing lost at the back |
| SB## | 24, 30, 33, 36, 42 | Sink base: false drawer front, clear inside for plumbing (the 24″ takes a single bowl up to 20″) |
| BTC## | 18 (24 via sales) | Waste pull-out — a drawer face hiding two bins |
| BMC## | 24, 30 | Base microwave opening with a drawer below |
| BSR## | 9, 12 (6 via sales) | Spice-rack pull-out for the gap you could not fill |
Sizes marked via sales are made, but they are not in the planner’s self-serve catalogue — ask your Flip sales rep for them.
A standard B## gives you a 6″ drawer and a big cupboard you have to kneel to see into. A DB##-3 gives 6 + 12 + 12 and everything comes to you. The usual compromise: drawers where you cook and where you keep pots, doors under the sink and at the far ends.
Wall cabinets are 12″ deep and come in heights of 12, 15, 18, 21, 24, 30, 36 and 42″. The tall three — 30, 36 and 42 — are the working uppers; the short ones bridge over a fridge, a range hood or a window.
| Height | Widths available | Where it goes |
|---|---|---|
| 12″ | 21–36 | Over a fridge, over a hood, over a doorway |
| 15″ / 18″ | 24–36 | Over a fridge or an over-the-range microwave |
| 21″ | 30–36 | Above a window run, or a low ceiling |
| 24″ | 24, 30–36 | The same, with a little more inside |
| 30″ | 9–36 | The classic upper — tops out at 84″, leaves a soffit gap |
| 36″ | 9–36 | Tops out at 90″ — more storage, still reachable |
| 42″ | 9–36 | Tops out at 96″ — meets an 8 ft ceiling exactly |
Widths run 9″ to 36″ in 3″ steps at 30, 36 and 42″ high; the short boxes start wider, as the table shows, and their few narrower sizes come via sales. A wall cabinet 27″ or wider takes two doors; narrower ones get a single door you can hinge left or right. Useful variants worth knowing: WSL (a single lift-up door on a gas strut, for over a sink or a peninsula), WMC (an open microwave shelf, 18″ deep so the machine actually fits), and the fridge-depth wall cabinets at 24″ deep that make a standard fridge look built in.
Tall cabinets are 24″ deep — the same as your base run — and come in three heights: 84″, 90″ and 96″, to match whichever wall-cabinet height you chose so the tops all land in one line.
| Family | Widths | What it holds |
|---|---|---|
| PC#### | 15, 18, 24, 30 | Pantry: a 30″ door at the bottom, a tall door above |
| OC30## | 30 | Single wall oven, with drawers beneath |
| DOC30## | 30 | Double wall oven |
| MOC30## | 30 | Microwave over oven, drawers below |
An oven tower is the one cabinet you cannot improvise: the appliance cut-out is a fixed opening, so pick the appliance before you order the cabinet. And remember a tall cabinet is 24″ deep — put one in the middle of a run and it will stand a foot proud of the 12″ uppers on either side of it, which is exactly why it belongs at the end of a run.
Corner cabinets are the one place where the width on the label is not the space it occupies, and it is where most first-time plans go wrong. There are three approaches, and they are not interchangeable.
Start every wall from the corner and work outward, because a corner cabinet is the one piece whose size you cannot adjust later. Get the corner wrong and the error travels along the entire run — and lands on the last cabinet, next to the fridge, where you will notice it every day.
These are not cabinets, and they are the single most common thing missing from a first order. Every one of them exists because real walls are not straight and real cabinet sizes do not add up to your room.
| Part | Size | What it saves you from |
|---|---|---|
| Base filler | 3″ or 6″ × 34½″ | The leftover inch at the end of a run; door-to-wall clearance |
| Wall filler | 3″ or 6″ × 30/36/42″ | The same problem, one row up |
| Tall filler | 3″ or 6″ × 96″ | Beside a pantry or a fridge surround |
| Base end panel | ¾″ × 34¾″ | A plain box side showing at the end of a run |
| Wall end panel | ¾″ × 12″ deep | The same, above |
| Dishwasher panel | 3″ wide | A dishwasher at the end of a run with nothing to screw to |
| Toe kick | 96″ × 4½″ | Cut to length on site and clipped on last |
| Crown / light rail | 96″ sticks | The gap at the ceiling; the wiring under the uppers |
Two details worth knowing. End panels are made 34¾″ high — a quarter-inch taller than the cabinet — so they can follow a floor that isn’t level: levelled on its legs to one line, each cabinet on an ordinary floor stands 34½″ to 34¾″ above the floor beneath it, and you scribe the panel’s bottom edge to match. And trim is sold in 8 ft sticks, so a 9 ft run of crown costs two sticks, not one and an eighth. Order 10% extra for test cuts; you will use it.
Snapping an end panel into a gap · 0:22Top trim for flat and Shaker doors · 1:47
Say the wall measures 144″ at its narrowest of three readings, runs from an inside corner to a side wall, and has to take the sink with a dishwasher to its left. Work from the corner out:
| Piece | Takes | Running total |
|---|---|---|
| BBC36-42 blind corner | 42″ | 42″ |
| DB24-3 drawer base | 24″ | 66″ |
| DW24 dishwasher opening | 24″ | 90″ |
| SB30 sink base | 30″ | 120″ |
| B18 base | 18″ | 138″ |
| Filler at the side wall | 3″ | 141″ |
| Left over | 3″ | 144″ |
That last 3″ is not a mistake — it is the margin that makes the job installable. Scribe it into the fillers at each end, and the run drops in even though the wall is out of square. A plan that comes to exactly 144″ is a plan that will not fit. Leave yourself a filler at every end, at every corner, and beside every appliance. If the boxes are already here and the run is too long or too short, this is what to do about it.
Nearly every size on this page is already in the free planner’s catalogue — drop cabinets on a wall, and it tells you what is left over and where the fillers go. It is a good deal faster than a spreadsheet, and it will not let you order a run that is an inch too long.
Base cabinets are 34½″ high and 24″ deep, in widths from 12″ to 36″ in 3″ steps, plus 42″ — with a 1½″ countertop that puts the work surface at 36″. Wall cabinets are 12″ deep in heights of 12, 15, 18, 21, 24, 30, 36 and 42″. Tall pantry cabinets are 24″ deep and 84, 90 or 96″ high.
Letters are the family, the first two digits are the width and the next two are the height. B18 = a base cabinet 18″ wide (base height is always 34½″, so it is not written). W3030 = a wall cabinet 30″ wide by 30″ high. SB36 = a 36″ sink base. Suffixes add detail: DD is double doors, FD is a full-height door, -3 means three drawers.
54″ to the underside is the standard: 19½″ above the 34½″ base cabinets, which leaves the usual 18″ of backsplash above a 36″ counter. From there the height of the cabinet decides where the kitchen stops: a 30″ upper ends at 84″, a 36″ at 90″, and a 42″ at 96″ — an eight-foot ceiling exactly.
24″ for base and tall cabinets, 12″ for wall cabinets. With a 1½″ countertop overhang the finished counter is about 25½″ deep. Over-fridge wall cabinets are also made 24″ deep so their faces line up with the fridge instead of floating a foot behind it.
Because it is the recess your toes need when you stand at the counter, and because it is included in the 34½″ total — the cabinet box itself is 30″ tall and it sits on legs. That also means the toe kick is where you take up an out-of-level floor: the adjustable feet do the work and a clip-on board hides them.
A short wall cabinet, typically 12″, 15″ or 18″ high, hung so its underside clears the fridge — usually around 72″ off the floor. Ordering it 24″ deep instead of 12″ is the trick that makes a standard-depth fridge look built in.
No — the ladder is 3″ steps (12, 15, 18, 21, 24, 27, 30, 33, 36, then 42). That is why fillers exist: your wall will never be a multiple of 3″, so you make up the difference with a 3″ or 6″ filler that gets scribed to the wall.
Because a blind corner occupies more wall than the box is wide. BBC36-42 is a 36″ cabinet that consumes 42″ of the wall once its filler pulls it clear of the corner, so the doors on both walls can open. Plan with the second number, or the run will not fit.
A base cabinet has one adjustable shelf (a sink base has none). A wall cabinet has none at 12″ high, one from 15″ to 24″, two at 30″ and 36″, and three at 42″. Shelves sit on pins in a drilled column, so you can move them — and buy extras if you want the spacing tighter.
Only height, and therefore where the kitchen stops. A 30″ upper leaves a foot of gap under an 8 ft ceiling — a dust shelf or a place for a soffit. A 36″ leaves half a foot. A 42″ goes right to the ceiling: the most storage, the cleanest line, and a top shelf you need a step stool to reach.
You can, and it is a deliberate design move — a 15″ deep upper over a coffee station, or a 24″ deep pantry at the end of a 12″ wall run. The rule is to put the deeper piece at the end of a run rather than in the middle, and to add an end panel so the change of depth reads as intentional instead of accidental.
Plan a filler at every end of every run, at every inside corner, and beside every tall appliance — and expect to lose 1–3″ in total on a typical wall. That leftover is not waste; it is what lets a rigid row of boxes fit a room that is out of square.
The free planner has this catalogue in it — real widths, real heights, real corners — and it does the leftover maths as you go.
Plan your kitchen free in 3D →