Post construction cleaning is the work most often priced by a rate per square foot and least suited to it. The variable that dominates the hours is not area but condition, and condition is decided by trades who are not your customer and who will still be finishing when your crew arrives. A rate quoted from a floor plan is a guess about somebody else's schedule, which is why this is the work where contractors most often lose money on a job they were happy to win.
Price in phases, because the work is in phases
A rough clean during construction: debris removal, sweeping, making areas usable. A final clean once trades are out: dust from every surface, fixtures, glass, floors. And a touch-up before handover, after the snagging trades have been through again. Each is a different scope at a different rate, and quoting one price for all three is how a single visit becomes three unpaid ones.
Condition, and the assumptions to write down
State what the price assumes: that debris and materials have been removed by others, that power and water are available, that the site is weathertight, and that trades have finished in the areas being cleaned. Then state what happens when those are untrue, which is an hourly rate or a re-quote. Without those lines the difference between the site you quoted and the site you arrive at is absorbed entirely by you.
Costing it honestly
Estimate hours by area and condition, using your own rates from previous builders cleans rather than a published figure. Load the wage with employer payroll tax and insurance. Add consumables generously, because post construction work eats cloths, filters and pads. Add equipment wear, which is heavier here than in routine cleaning. Then apply the margin by division, and check the result per square foot only as a sanity test.
Questions people ask about commercial post construction cleaning rates
Can post construction cleaning be priced per square foot?
It can be expressed that way after costing, but not derived that way. Condition moves the hours far more than area does.
Who removes the debris?
Say so in the quote. It is the single most common scope dispute on this work and it is a one-line fix.
How many visits should I quote?
Usually three: rough, final and touch-up. Quoting one and being asked back twice is the default failure mode.