How to Estimate a Deck Building Job: 2026 Contractor’s Guide

Why deck bids lose money

A deck is carpentry over a frame the customer never sees. They price the boards they walk on. You carry the ledger, the joists, the footings, the hangers, and the permit. Bid off surface square feet and the frame eats the job.

Anchor the labor in real carpentry wages. The Bureau of Labor Statistics counted 670,090 carpenters at a $29.12 median hourly wage in May 2025. A deck is carpentry first and decking second.

How to estimate a deck building job in 8 steps

1. Measure the footprint and the conditions

   Length times width gives you square feet. Then write down what actually moves the number: height above grade, whether the deck ties to the house or free-stands, and any tiers, angles, or curves. Two 300 square foot decks can price thousands apart.

2. Price the decking surface off your own yard

   No primary source publishes decking prices per square foot, and the number moves with region, supplier, grade, and profile. So price it yourself: take today’s per-board cost, divide by the square footage one board covers, then multiply by deck area.

3. Take off the substructure

   Ledger, beams, joists, posts, and blocking. Joist spacing drives the count, and code sets the spacing. The 2021 International Residential Code caps joists at 16 inches on center under 1 and 1/4 inch decking running perpendicular over three or more joists, and 12 inches diagonal. Over two joists it is single span and the caps drop to 12 and 8.

4. Count footings and price the concrete

   Footing count follows the beam and post layout. Depth follows geography. The American Wood Council guide DCA 6 puts footings on undisturbed soil at least 12 inches down or below the frost line, whichever is deeper. Price volume, forms, post bases, and the dig.

5. Take off railings and stairs

   Code sets the trigger. Section R312.1.1 requires a guard on any open-sided walking surface more than 30 inches above the floor or grade below, and Section R312.1.2 sets the minimum guard height at 36 inches. Measure railing by linear foot. Price stairs by riser count, run, stringers, and tread.

6. Tally hardware and flashing on their own line

   Hangers, post bases and caps, hurricane ties, structural screws, the deck-board fastener system, and the ledger flashing. Buried in a vague lumber line, all of it gets underbid. Code is specific here: ledger fasteners must be hot-dipped galvanized or stainless, and metal flashing at least a nominal 0.019 inch thick.

7. Add the permit and the waste

   Most jurisdictions require a permit for a deck above a threshold height or area, and it carries a fee plus inspections. Put the fee, the plan review, and your own time on the estimate. Then build waste per component off the real cut list.

8. Calculate labor, then stack overhead and profit

   Start at the $29.12 carpenter median. The 10th percentile is $19.43 and the 90th is $48.03. Then apply a loaded multiplier for payroll taxes, workers comp, liability, truck, fuel, and tools. Loaded cost is a business.

Turn a photo of the yard into an itemized deck estimate, free →

What the deck has to sell for

Direct cost is material plus loaded labor. Overhead and profit stack on top of it. Say direct cost runs $9,000, overhead is 20 percent of revenue, and target net margin is 10 percent. Combined that is 30 percent, so the customer number is $9,000 divided by 0.70, or roughly $12,860. About a 43 percent markup.

Markup and margin are not the same number, and that gap is where small shops disappear. A 15 percent markup leaves about a 13 percent margin on revenue. Our cost to build a deck guide walks the full stack, and the framing estimate guide covers the substructure takeoff.