This calculator vs. a flat rate per square
“$X a square, any siding job” is a price for one story count, one material, and one tear-off situation, quietly applied to a taller house with heavier material and old siding to strip that the flat number never carried.
What a flat rate per square is
A flat rate per square (100 square feet of wall) is the fastest way to quote a siding job over the phone: multiply the billable squares by a number and read it back. Homeowners like it because it is easy to compare against a competitor's quote, and it is the number a customer holding one will ask you to match.
The number behind it was usually set for the simplest version of the job — a one-story vinyl re-side over sound existing siding, with no tear-off and light trim — and then reused for every job afterward, whether or not the next one is two or three stories, heavier material, a full tear-off with a dumpster, or an elevation set with far more trim and openings.
What this calculator is
This page keeps no account and sends nothing to a server. You enter each wall's length and height, openings, waste, material, stories, whether the job needs tear-off and housewrap, trim by the linear foot, and any add-ons, plus your own wage, payroll burden, material costs, overhead, and target margin. It prices siding material and install labor from the actual billable squares and story multiplier, tear-off and housewrap as their own lines only when the job needs them, openings by count, and trim by the linear foot — for this job, not a flat rate for every job.
| What a flat rate per square does | What this calculator does instead |
|---|---|
| Charges the same per square whether the house is one story or three, even though a taller wall needs more staging and reach per square installed. | Multiplies install labor by a story factor — 1.35× for two stories, 1.7× for three — from the actual story count, not a single height for every job. |
| Has no line for tear-off or a dumpster, even though stripping old siding and hauling it away is real labor and a real disposal cost a re-side over sound siding never needs. | Prices tear-off labor and a dumpster as their own line, only when the job needs them. |
| Has no line for housewrap, even though wrapping the house before the new siding goes up is priced by net wall area and is not always part of the job. | Prices housewrap from the actual net wall square footage, only when the job includes it. |
| Has no line for opening count, even though each window and door adds real labor to trim out regardless of house size. | Prices opening labor from the actual count of windows and doors. |
| Has no line for starter strip, corners, J-channel, or undersill trim, even though trim is priced by the linear foot and does not track wall area. | Prices each trim item from its own linear footage, separate from the siding itself. |
Two houses, one flat rate
Using this calculator's own figures, at a 28% target margin, a $32 hourly wage, and 34% payroll burden:
A one-story vinyl wrap with no tear-off costs $4,892.04 to run and this calculator prices it at $6,794.49 for 8.91 billable squares — $762.57 per square. A two-story fiber-cement tear-off with housewrap and heavier trim costs $22,874.89 to run and this calculator prices it at $31,770.68 for 19.31 billable squares, 4.68 times the vinyl job's price on just 2.17 times the squares. Quote the fiber-cement job at the vinyl job's flat $762.57-per-square rate instead, and 19.31 squares prices at $14,724.30 — $8,150.59 short of the $22,874.89 it costs to build. The flat rate does not just erode the margin here: it prices the job at a loss before it ever clears its own cost.
Common questions
Why does a flat rate per square get a bigger siding job wrong?
Because almost nothing in a siding job scales with squares alone. A second or third story multiplies install labor for staging and reach, not material. Tear-off adds a labor line and a dumpster that a re-side over existing siding never needs. Housewrap is priced by net wall area, not billable squares. Openings add labor per window and door regardless of house size, and trim -- starter strip, corners, J-channel, undersill -- is priced by linear feet, which does not track wall area the way a flat per-square rate assumes. A rate set on a simple one-story vinyl wrap carries none of that, because a simple one-story job does not have it to carry.
What does a flat per-square rate usually leave out entirely?
Story height, tear-off and dumpster, housewrap, opening count, and linear trim. A flat per-square number has no line for the extra staging and reach a second or third story adds to install labor, no line for stripping old siding and hauling it away, no line for wrapping the house before the new siding goes up, no line for the labor each window and door opening adds regardless of house size, and no line for corners, starter strip, J-channel, and undersill trim priced by the linear foot.
How big is the pricing gap in practice?
Using this calculator's own figures at a $32 hourly wage, 34% payroll burden, and a 28% target margin: a one-story vinyl wrap with no tear-off costs $4,892.04 to run and this calculator prices it at $6,794.49 for 8.91 billable squares -- $762.57 per square. A two-story fiber-cement tear-off with housewrap costs $22,874.89 to run and this calculator prices it at $31,770.68 for 19.31 billable squares, 4.68 times the vinyl job's price on just 2.17 times the squares. Quote the fiber-cement job at the vinyl job's flat $762.57-per-square rate instead, and 19.31 squares prices at $14,724.30 -- $8,150.59 short of the $22,874.89 it costs to build.
Is a flat rate per square ever the right way to quote?
For a job close to the story count, material, and tear-off situation the rate was set on -- typically a one-story vinyl re-side with no tear-off and light trim -- a flat per-square number can land close, because that is probably the job the rate was set on. The risk is quoting a taller house, a heavier material, a tear-off, or a trim-heavy elevation set at the same rate, because the rate does not know the stories, the material, or whether the old siding comes off until someone measures the walls, and by then the flat number has often already been quoted over the phone.
Does this calculator know my local labor rates or material costs?
No. It has no data on your local labor market, your supplier's material pricing, or what other siding contractors in your area charge. It takes per-elevation wall measurements, waste, material, stories, openings, tear-off, housewrap, and trim you supply, plus your own wage, burden, overhead, and target margin, and turns that into a price for this job -- the arithmetic a flat rate per square skips, not a market survey.
Open the Siding Bid Calculator to price your own job, or read how much should I charge for vinyl siding.