Measure once, order once. Here is how to capture a room that is never quite square or level — walls, windows, outlets and all — so the cabinets you order actually fit.
Everything downstream — your design, your order, your install — inherits the numbers you write down today. Measure carefully now and the rest of the project runs smooth. Measure loosely and you pay for it later in filler strips, returns, and cabinets that almost fit.
Draw a rough top-down plan of the kitchen on graph paper (or the printable worksheet). Label each wall A, B, C going clockwise, mark where the door and window openings are, note which way doors swing, and write the ceiling height in a corner. You are not drawing to scale — you are making a place to hang every number you are about to collect.
Write every number in inches. Not feet-and-inches, not centimetres, and never a mix on the same page — cabinets are ordered in inches, and 146″ cannot be misread the way 12′ 2″ can at 9 p.m. three weeks later. Work to the nearest 1/16″, and when a reading falls between marks, round down. A wall that turns out 1/8″ wider than you wrote is a filler; a wall 1/8″ narrower is a cabinet that will not go in.
Mostly, yes. A tape hook bites on an outside corner and will hold a 12′ run on its own. What is genuinely awkward solo is the diagonal square check and ceiling heights, where the blade flexes and reads long — brace the hook against a scrap block wedged in the corner, or borrow someone for the last twenty minutes. Either way, measure the whole room twice, on two different days. Almost every ordering mistake traces back to a number that was only ever written down once.
What they search at midnight “my kitchen walls aren’t square / aren’t straight” — they rarely are. Measure like they’re crooked and you’ll never be surprised.
Measure each wall corner to corner, and do it at three heights: near the floor (about 6″), at counter height (about 36″), and up where the wall cabinets land (about 84″). Walls bow, so these three numbers will not match. Write down the smallest one — that is the space your cabinets actually have to fit into. Building to the widest measurement is how a run ends up too long.
Plain wall is easy. What trips people up is everything in the wall. For each item, record its position along the wall and its height, measuring to the nearest useful edge:
Appliance sizes and their door swings. A fridge needs room for its door to clear the counter; a range needs clearance to a side wall; a dishwasher door drops into the walkway. Measure the appliances you already own, and leave their real footprints on your sketch.
Cabinets are built square; rooms rarely are. The quick test: measure the two diagonals of the room (or of a rectangular corner). If the diagonals are equal, the corner is square. If they differ, you know exactly how much scribing and filler to plan for — before you order, not during install.
Knowing the standard sizes turns raw wall numbers into a real plan. These are the North-American norms your measurements need to accommodate:
| Cabinet | Depth | Height | Widths |
|---|---|---|---|
| Base | 24″ | 34½″ (+ counter ≈ 36″) | 9–48″ · 3″ steps |
| Wall | 12″ | 30 / 36 / 42″ | 9–48″ · 3″ steps |
| Tall / pantry | 24″ | 84 / 90 / 96″ | 18 / 24 / 30″ |
| Toe kick | — | 4½″ high | runs the base |
Two more numbers to hold onto: countertops overhang the base by about 1″ at the front, and wall cabinets typically sit with their bottom 54″ off the floor, leaving a 15–18″ gap above the counter.
Measure each wall at three heights and use the smallest reading, then check the corner with the diagonal test: measure both diagonals of the space, and if they differ the room is out of square. Plan a scribe and filler on that side rather than forcing cabinets to fit.
Base cabinets are 24″ deep and 34½″ high (about 36″ with a countertop); wall cabinets are 12″ deep and 30, 36 or 42″ high; tall/pantry cabinets are 24″ deep and 84–96″ high. Widths run 9–48″ in 3″ steps.
Leave a walkway of at least 42″ (48″ for two cooks), 36–42″ between an island and a run, and enough room for every appliance door — fridge, range and dishwasher — to swing clear of the counter.
Measure to the finished drywall surface, since that is what the cabinets sit against. Note stud locations separately — you will need them for the install, but they do not change the width the cabinets fit into.
Standard is the bottom of the wall cabinets at 54″ off the finished floor, which leaves a 15–18″ gap above a 36″ countertop. Taller people sometimes raise them slightly; keep it consistent across the kitchen.
Most fridge cabinets are 36″ wide to match a standard fridge opening (add fillers to reach about 37″ of clearance). Depth is a choice: a 12″ cabinet is cheapest and stores plenty, while a 24″-deep one sits flush with the fridge front for a built-in look but needs a side panel or wall to support it. Leave roughly 1″ of wiggle room around the fridge.
A sink base is usually 30″ or 36″ wide — the bowl has to fit between the side panels with room to spare. For an undermount sink, keep the sink’s outside width about 3″ under the cabinet’s inside width so there is room for the mounting clips and a support rail; a 36″ base comfortably takes a 30–33″ sink.
Letters are the type, numbers are the size in inches. B = base, W = wall, SB = sink base, DB = drawer base, BBC/WBC = blind corner, TP = tall pantry. Base and tall codes carry only the width, because height and depth are standard — B18 is an 18″ base. Wall codes carry width then height — W3030 is 30″ wide by 30″ high. Anything non-standard gets spelled out on the end.
It depends entirely which way, and the two directions are not equal. Measuring short — the wall is actually wider than you wrote — is survivable: a slightly wider filler absorbs it and nobody will ever see it. Measuring long is the expensive one: the run does not fit, and you are either pulling a cabinet out of the plan or re-ordering. That asymmetry is the entire reason for the round-down rule and for keeping a filler at each end of every run. Caught before ordering, re-measure. Caught after delivery, change the plan before you cut anything — swapping a 24″ cabinet for an 18″ plus filler is a two-minute redraw in the planner.
Drop your wall lengths and openings into Flip’s free 3D planner and it lays out a real, buildable kitchen — exact cabinet sizes and filler locations included — so you can see it fit before you order.
Open the 3D planner →