Twenty-one hours before the first sheet is cut
A kitchen costs the shop a block of time before any plywood goes on the saw. Shop plans and the cut list, the site visits and meetings with the homeowners, the paint sample, the paperwork and cleaning the shop down after: in the example that adds up to 21.25 hours. At $59 that is $1,253.75, or about $63 on every foot of a 20 ft kitchen.
Then each foot of cabinet takes 135 minutes in the shop, from cutting sheet goods to hanging doors and fitting drawers. Those two numbers, once per kitchen and per foot, are the ones to track on your own jobs. Get them from a finished kitchen's timesheets, not from memory.
Vanity at $655 a foot, 45 ft kitchen at $375
The break table runs the same cabinet at 8, 20, 30 and 45 feet. An 8 ft vanity run comes to $655.38 a foot, the 20 ft kitchen to $450.74, 30 ft to $405.27 and 45 ft to $374.95. One foot price for every job either loses money on the small ones or loses the big ones to a cheaper bid.
That is the plain answer when a customer asks why their bathroom costs more per foot than their neighbor's kitchen. The hours at the start do not shrink with the room.
Drawer boxes grow with the kitchen
The three named lines below the materials are a fixed amount per order, so check them when the size changes. The bought-in dovetail drawer boxes are $805 for 20 ft. On a 45 ft kitchen with the same drawer layout they would be about $1,810, and the foot price goes from $374.95 to $401.75 once you update that line.
Crown, fillers and toe kick work the same way: more wall, more trim. The calculator will not guess this for you, so treat those boxes as part of each new quote, not as defaults to leave alone.
How the spreadsheet reaches $489.73 a foot
The quick version has no machine costs for the saw, edge bander and spray booth, no markup on the bought-in drawer boxes and no safety cushion. The spreadsheet adds all three, walks through the cabinet costs owners forget line by line, prints a customer quote with your terms and tracks each kitchen's real hours in a job log. Its version of the same kitchen is $489.73 a foot.
The $59 rate is the example shop's, not yours. See how the sample gets to $58.80 on the cabinet shop hourly rate page, work out your own with the free true hourly rate calculator, and read the custom cabinet pricing guide for the walnut, paint and install questions. The difference between 15% markup and a 15% margin is in the markup vs margin guide.