This calculator vs. a flat $28-a-foot deck estimate
"$28 a foot" is not a price for a deck — it is a price for a low, simple platform near grade, quietly applied to an elevated deck with railing, a stair run, and an old deck to haul away.
What a flat $28-a-foot estimate is
A flat per-square-foot number is the fastest way to answer "how much for a deck?" over the phone or in a search result: one rate, multiplied by length times width. Homeowners hear it as a rule of thumb and expect a bid to land near it, and it is the number a caller holding a competitor's postcard will ask a crew to match on their own footprint.
The rate behind it was set for one job — usually a low platform close to grade, with no railing, no stairs, and nothing to tear out — and then reused for every deck afterward, whether or not the next one is a third off the ground, wrapped in railing, reached by a stair run, or built on top of an existing deck that has to come out first.
What this calculator is
This page keeps no account and sends nothing to a server. You enter each surface's length, width, height above grade, and material, plus railing lineal feet and style, stair runs by riser and width, and square footage of an existing deck to tear out, along with your own wage, payroll burden, travel, and overhead. It prices the height, the railing, the stairs, the footings, and the tear-out separately, and returns a walk-away price and price per square foot below which the job loses money — for this deck, not a generic one.
| Job | $28-a-foot estimate | Walk-away price | Verdict |
|---|---|---|---|
| 20×20 patio deck, 10 inches off grade, no railing, no stairs, no tear-out (400 sf) | $11,200.00 | $10,773.09 | Covers, $426.91 to spare |
| 14×20 main deck + 10×12 wrap, both 3 ft up, 46 lf wood railing, 1 stair run, 280 sf tear-out (this calculator's own default job, 400 sf) | $11,200.00 | $17,692.80 | Short $6,492.80 |
| 16×24 elevated composite deck, 8 ft up, 80 lf cable railing, 14-riser stair (384 sf) | $10,752.00 | $29,826.09 | Short $19,074.09 |
Worked using this calculator's own material and railing presets at a $42 hourly wage, 30% payroll burden, 15% overhead on direct cost, and a 22% target margin — the form's own shipped defaults, not numbers invented for this page. Open the calculator to check any row yourself.
Notice the middle row: it is this calculator's own shipped starting point, not a job picked to prove a point, and it already runs $6,492.80 over a $28-a-foot estimate on the identical 400 square feet the low patio in the first row covers with room to spare. Nothing about it is extreme — a few feet of height, one stair, ordinary railing, and hauling away the old deck is the difference.
| What a flat $28-a-foot estimate does | What this calculator does instead |
|---|---|
| Charges the same rate whether the deck is 10 inches off grade or 8 feet up — an elevated frame needs more posts, usually a guard, and more framing and post-set hours than a low platform of the same footprint. | Applies extra framing and post-set hours once a surface crosses the guard-height and elevated-height thresholds, so a low deck and a tall deck of the same square footage price differently. |
| Has no separate line for railing, so a deck wrapped in 80 lineal feet of cable rail gets the same per-square-foot number as one with none at all. | Prices railing by the lineal foot and by style — wood, aluminum, cable, or glass — on top of the deck surfaces, scaled to the run entered. |
| Prices "a deck" the same whether or not it needs a stair run, and has no way to see risers or stair width. | Adds stair hours and material per run, scaled to riser count and width, only when stairs are entered. |
| Has no line for hauling away an existing deck, so a rebuild on the same footprint costs the same as building on a bare lot. | Prices demo hours and disposal per square foot of tear-out separately, on top of the new build. |
| Gives the homeowner a number to hold a crew to, not a number the crew can check a quote against once the deck turns out to be elevated, railed, and stepped after the estimate was already given. | Reports the walk-away price and price per square foot for the job as entered, so a shopped rate can be scored against real cost before it is confirmed. |
A flat $28-a-foot estimate is not wrong because it is simple — it is wrong when it is applied to a height, railing run, stair count, or tear-out condition it was not set on, and "square feet" alone never tells you that has happened. This calculator does not replace judgment about your market; it replaces the arithmetic a flat rate skips.
Common questions
Why does a flat $28-a-foot deck estimate get the price wrong?
Because deck cost scales with height above grade, railing lineal feet, stair runs, footings, material, and tear-out — not with square footage alone. A 14x20 patio ten inches off grade and a 14x20 elevated deck eight feet up are the same 280 square feet and completely different jobs. A flat per-square-foot rate quotes both the same and is wrong on one of them every time.
What does a flat per-square-foot deck estimate usually leave out entirely?
The height above grade, the railing, the stairs, the footings, and the tear-out. A published per-square-foot rate is set on one configuration — usually a low platform close to grade, no railing, no stairs, no existing deck to remove — and has no separate line for the extra framing and post-set hours a guard-height or elevated deck needs, for railing priced by the lineal foot rather than the deck's footprint, for a stair run's risers and width, or for hauling away what was there before.
How much do height, railing, stairs, and tear-out actually add over the estimate?
On this calculator's own worked examples, at a $42 hourly wage, 30% burden, 15% overhead, and a 22% target margin: a low, simple 20x20 patio deck ten inches off grade, with no railing, stairs, or tear-out, walks away at $10,773.09, comfortably under a $28-a-foot estimate on the same 400 square feet ($11,200.00). This calculator's own shipped default job — a 14x20 main deck plus a 10x12 wrap, both three feet up, 46 lineal feet of wood railing, one five-riser stair, and 280 square feet of tear-out — walks away at $17,692.80, $6,492.80 over that same per-square-foot number on the same 400 square feet. A 16x24 elevated composite deck eight feet up, with 80 lineal feet of cable railing and a 14-riser stair, walks away at $29,826.09, $19,074.09 over a $28-a-foot estimate on its 384 square feet.
Is a flat $28-a-foot estimate ever the right way to quote?
For something close to the easy job it was probably priced on — a low platform near grade, no railing, no stairs, nothing to tear out — a flat per-square-foot rate can land close or even leave room to spare. The risk is guard height or an elevated frame, railing by the lineal foot, a stair run, or a tear-out stacking on top of each other, because a rate quoted per square foot has no way to see any of them until the framing is already up.
Does this calculator know what to charge in my market?
No. It has no data on local rates or what competitors charge. It takes the surfaces, height, material, railing, stairs, and tear-out you enter, plus your own wage, burden, and overhead, and turns them into a walk-away price for the deck you describe — the arithmetic a flat per-square-foot rate skips, not a market survey.
Nothing here says or implies that quoting a flat $28-a-foot estimate is a bad-faith practice — it is a common, honest shortcut that works until the job stops matching the height, railing, and tear-out condition it was set on. This page describes where that shortcut breaks down, not a fault in anyone who uses it.
Open the Deck Bid Calculator and price your own job.