Every cabinet reading level does not mean the run is flat. Those are two different measurements and the fabricator checks the second one.

Measure the plane with a laser, not the boxes with a level

The standard is flat and level within an eighth of an inch over ten feet, and the tool has to match the span. A four foot level tells you whether one cabinet is level and tells you nothing about whether eight of them share a plane. Set a laser line across the whole room before you start hanging anything, refer every cabinet to that single reference rather than to its neighbor, and record the deviation at each top as you go. Referring each box to the one beside it is exactly how a run accumulates a quarter inch of drift with every individual reading looking perfect, which is the failure the standard exists to catch.

Fix the plane on top of the cabinets, not by moving them

This is the professional answer to a real conflict, and it is worth knowing before a fabricator proposes the alternative. In the documented case, the suggested fix was to lower one cabinet a quarter inch and raise another a quarter inch, which satisfies the stone and destroys the cabinetry, because the tops and doors no longer line up. A cabinet leveling specialist writing for a trade journal describes the correct approach: where cabinets cannot be lifted without damage they are leveled at the top with shims, layering eighth and quarter inch hardboard strips as needed, gluing and tacking them to the top edge, then belt sanding down to a laser line. A forum respondent reached the same conclusion independently, suggesting adding material to the top of the low boxes so you do not have to mess with the doors. Build the plane above the boxes and leave the face alignment alone.

Expect a gap after shimming, and plan the trim for it

Shimming the tops raises the countertop off the cabinet where the shims are thickest, and the specialist notes that this typically leaves a gap between the countertop and the cabinets. That gap is not a defect, it is the geometry of the fix, and it gets covered with trim. The detail that matters is sizing: the trim has to be chosen with attention to drawer and door clearances so it does not interfere with anything opening. Working that out before the stone is set is straightforward; discovering after installation that a trim piece fouls the top drawer is not. If a run is going to need meaningful shimming, decide the trim at the same time.

Replacing laminate with stone is the case that fails, and it fails for a reason

The most common way people meet this standard is by upgrading an existing kitchen, and the specialist is direct about the odds: if clients currently have a laminate-type countertop, their cabinets probably do not meet the recommendation. That is not a criticism of whoever installed them. Laminate is far more forgiving of an imperfect plane than stone is, so the cabinets were never tested against this number and nobody had any reason to find out. Which means a laminate-to-stone job should be quoted with the expectation that the tops will need leveling work, rather than treating that as an unwelcome surprise partway through.

There is a per-cabinet limit as well as a per-run one

Two numbers apply and satisfying one does not satisfy the other. One fabricator checklist asks for every run to be checked with a four foot level, noting any high or low spot greater than an eighth of an inch, and separately says that any single cabinet more than three sixteenths of an inch out of level across its own width should be shimmed or planed down before templating. So a run can average within tolerance while containing one box that is individually unacceptable, and a run of individually acceptable boxes can drift out of plane. Check both, and record both, because a templater will.

Straightness is a separate problem, and the overhang exposes it

Level gets all the attention and straightness gets none, right up until the stone is down. One fabricator’s published tolerances note that overhangs follow the line of the front of the cabinet run, and that if cabinets are severely out of straightness the overhang will vary throughout the run. That is a highly visible defect on a finished kitchen, because the human eye reads the shadow line under a countertop edge very well. Pull a string or a laser along the front faces of the base run as a separate check from the level check, and correct it while the cabinets are still adjustable rather than explaining it afterward.

The walls are not straight either, and the template has to know

A countertop meets the wall along its whole back edge, and walls bow. A fabricator checklist advises running a straightedge along the wall and marking any bow or gap, because it affects how tightly the top fits at the back. The same source makes a related point that separates a good template from a bad one: cut the template material to fit the actual cabinet tops, not the drawings. Sloppy templates produce gaps at the wall and misaligned seams that no amount of caulk can fix. If a wall has a significant bow, that is a decision to be made deliberately, either scribing the stone to it or planning a backsplash that hides it, and it is much better made at template stage than at install.

Templating has a prerequisite list, and missing one item costs a week

The templating visit is short, roughly ninety minutes, and it cannot proceed without a specific set of things being physically present. Fabricator guidance is consistent: cabinets installed and level, the sink, faucet and cooktop actually on site rather than ordered, and the old countertops removed. Appliances in particular should be ordered six to eight weeks ahead, because a cooktop cutout cannot be templated without exact dimensions. When a homeowner forgets one item, templating gets rescheduled and the whole timeline shifts by about a week. Fabricators also report that most delays are not theirs but come from cabinet installation running behind or plumbing not being ready, which makes the coordination as much a part of this job as the carpentry.