The 7-Step Way to Measure a Kitchen Before You Cut a Single Board

Most bad cut lists don't start at the saw. They start a day or two earlier, with a tape measure, a notepad, and a wall nobody actually checked for square.

You can nest a sheet perfectly, get great yield, and still end up a panel short on site, or watch a corner unit sit half an inch off the wall it's meant to meet flush. Not because the software got it wrong. Because the number you fed it was wrong before you ever opened the laptop, and nothing downstream of a bad measurement can fix itself.

The fix isn't a fancier tape measure or a pricier laser. It's measuring in the right order, every time, so the room tells you the truth before the saw does. That's the whole point of this list — it's not new information, it's just the order most people skip under time pressure.

1Check the floor before you touch anything else

Measure floor to ceiling in three or four spots around the room, not just once near the door. Don't average those numbers. Use the lowest one you get, because older houses especially have floors that dip in the middle of a room or rise toward an outside wall — it's common enough that you should just expect it, not go hunting for it as a surprise. A sagging joist, a patched-in section, or just decades of settling can all be behind it, and it's rarely worth chasing down the cause before a job — just measure around it.

Base units get set level off the floor's high point, and everywhere else you shim down to match it. Set units off an average instead, and the low end of your run sits proud while the high end rocks — you won't see it until the doors are hung, the worktop goes on uneven, and nothing lines up with the wall cabinets above it. A long spirit level or a site-made story pole earns its keep here — mark the high point on it once, and you've got a single reference to carry to every cabinet in the run instead of re-measuring from scratch each time.

2Check the walls for plumb and square, not just length

Hold a four-foot level against both walls in every inside corner — a wall can look dead straight to the eye and still be a quarter inch out over its length, easy. Check plumb first, then square, then level, in that order, so each check builds on the last instead of chasing three problems at once. A spirit level will show you a small bump or dip that a laser often won't, because the laser just projects a straight line past it.

Measure each long wall at two different heights — skirting height and worktop height is a good pair — not just once along the floor, since walls bow out in the middle more often than people expect. If you find a bow, don't average it away. Note where it is and how much it moves, because that's what tells you how much scribe allowance you'll need — a commonly used figure is around half an inch for base and wall units, more for anything full height, though treat that as a starting point to check against the real wall, not a rule to apply blindly.

3Measure the diagonals, not just the walls

Stretch a tape corner to corner across the room or the opening, both ways. If the two diagonal readings don't match, the corner isn't a true 90 degrees — it's more like 89 or 91, and that small difference barely matters for a flat run of cabinets against a single wall.

It matters a lot the moment you're fitting a corner unit, because corner units have nowhere to hide the error the way a flat run can — the door either closes clean or it doesn't. Catch this on paper, before you've cut anything. Catching it with a half-fitted cabinet that won't sit flush costs a lot more than the five minutes the diagonal check takes, and it's a much harder conversation to have with a client standing in the room.

4Map every opening from one fixed point, not just the overall wall length

Don't just measure the wall end to end and call it done. Measure corner-to-window, corner-to-door, corner-to-radiator, corner-to-anything that breaks the run, using one corner as your fixed point for everything, every time. This catches the case where a window or doorway isn't actually centered where the room drawing says it is, which happens more often than anyone plans for.

Add your segments up and check the total matches the overall wall length you measured separately. If it doesn't, you've got a transcription slip or a measuring slip in there somewhere, and you want to find that now on a notepad, not after the sheets are already cut. Write down soffit depth and height, skirting thickness, window sill height, and where the flooring finishes if it isn't down yet — none of it looks important alone, but all of it eats into a cabinet's depth or height from somewhere you weren't watching, including dishwasher door swing and fridge clearance.

5Lock in plumbing, gas, and electrical before you measure for real

Sink, hob, and socket positions need to be fixed before your final measurements go on the cut list, not after. First-fix plumbing and electrics go in before the cabinets cover that section of wall, not the other way round. If that first-fix hasn't happened yet, your measurements are provisional, whatever the drawing says.

Gas work needs a Gas Safe registered engineer, and notifiable electrical work needs a qualified electrician — that's usually not the fitter's call to make on site. It is the fitter's job to confirm those positions are actually final and marked before anything goes on the cut list, not just planned on a drawing somewhere. Move a socket six inches after the panels are cut, and somebody has to explain the extra sheet — usually that's you, even though you didn't move it, and the client remembers whose name was on the job, not the electrician's.

6Snap one reference line and measure everything off it

Run a level line around the room with a laser or a chalk line, set at a height that makes sense for the job — worktop height is a common choice. Measure base cabinet heights up to that line, and wall cabinet heights down from it. You stop measuring up from an uneven floor every single time, and start working off one number you already trust, no matter how many cabinets are in the run. A self-leveling line laser on a tripod makes quick work of this on a bigger kitchen, but a chalk line and a level do the exact same job on a smaller one.

Worktops still get templated off the actual fitted units once they're physically in place, not off the drawing or the original cut list. By then small installation gaps have crept in everywhere — a shim here, a scribe cut there — and the real cabinet beats the plan every single time. Trust the thing you can put a tape on.

7Measure it all again before you cut, not after

A full re-check of every key number, right before anything gets cut, catches more mistakes than people give it credit for. Not a glance at the sheet — actually walk the room again with the tape in hand, the same way you did the first time. It takes ten minutes and it's the cheapest ten minutes in the whole job, every time, on every kitchen, no exceptions for the ones that feel straightforward.

If you used a scanning app to speed up the layout, this matters even more. Some of those apps quietly square off a wall that's actually out of true, because that's what the algorithm assumes a wall should be — the scan looks clean, but the wall underneath it isn't, and mirrors, glass, and bad lighting only make it worse. Use the app for the plan, then verify the longest wall and every opening with a tape or a laser before anything gets cut. That one extra pass is cheap. A missing panel on install day never is.

• Found the floor's high point in three or four spots, not an average of them
• Checked both walls for plumb in every corner with a four-foot level
• Measured long walls at two different heights to catch any bow in the middle
• Checked diagonals for true square, especially anywhere a corner cabinet is going
• Measured every opening from one fixed corner, then checked the segments actually add up to the total
• Confirmed plumbing, gas, and electrical positions are final and marked, not just planned on paper
• Marked one level reference line around the room and measured everything off it
• Walked the room a second time right before cutting, scanning app or not, with a tape in hand