Deck Cost Calculator

How much does a deck cost to build?

A deck cost calculator estimates the installed price from the deck’s footprint: total cost = length × width × (material rate + labor rate per square foot). A 16 × 12 ft deck is 192 square feet; at the default $15 material and $15 labor per square foot it comes to $2,880 + $2,880 = $5,760. The calculator splits the total so you can see how much is lumber and how much is the crew.

Square-foot pricing is how most deck builders give a first estimate. It is a budgeting tool, not a quote. Use it to compare sizes and materials, then get itemized bids.

The formula in plain words

1. Area = deck length × deck width, in square feet.
2. Material cost = area × material rate per square foot.
3. Labor cost = area × labor rate per square foot.
4. Total = material cost + labor cost.

Results round to the nearest dollar. The rates are blended: they should cover everything per square foot of finished deck, not just the boards you walk on.

Worked examples

Default deck: 16 × 12 ft, $15 material, $15 labor

• Area: 16 × 12 = 192 sq ft
• Material: 192 × $15 = $2,880
• Labor: 192 × $15 = $2,880
• Total: $5,760

Larger pressure-treated deck: 20 × 16 ft, $10 material, $12 labor

• Area: 20 × 16 = 320 sq ft
• Material: 320 × $10 = $3,200
• Labor: 320 × $12 = $3,840
• Total: $7,040

The second deck is two thirds bigger than the first but costs only about 22% more, because its rates are lower. Rates matter as much as size.

Total cost by size and blended rate

Deck size	Area	$20/sq ft total	$30/sq ft total	$45/sq ft total
10 × 10 ft	100 sq ft	$2,000	$3,000	$4,500
12 × 12 ft	144 sq ft	$2,880	$4,320	$6,480
16 × 12 ft	192 sq ft	$3,840	$5,760	$8,640
20 × 16 ft	320 sq ft	$6,400	$9,600	$14,400
24 × 20 ft	480 sq ft	$9,600	$14,400	$21,600

The blended rate is material plus labor. Enter them separately in the calculator to see the split.

What a per-square-foot rate should cover

Part	Usually in the rate?	Notes
Decking boards and fasteners	Yes	The visible surface
Joists, beams, ledger, posts	Yes	Ask if a quote leaves them out
Footings and concrete	Sometimes	Count and depth depend on code
Railings	Often separate	Priced per linear foot
Stairs	Often separate	Priced per step or per flight
Permit, demolition, hauling	Usually separate	Ask for each as a line item

How to measure a deck

• Measure the outer edges of the deck surface, in feet.
• Split L-shaped decks into two rectangles and add the areas.
• For multi-level decks, measure each level on its own.
• Count railing length and stair steps separately, since they are priced differently.

Common budgeting mistakes

• Using a boards-only price. Decking boards are only part of the material. The deck calculator and deck joist calculator count the framing.
• Forgetting railings on raised decks. Many codes require guards once a deck is about 30 in above grade. Check local code.
• Ignoring upkeep. Wood decks need stain or sealer every few years. Price it with the deck stain calculator.
• Comparing bids that differ in scope. One bid may include stairs and permits; another may not.

For material counts on a composite build, see the composite decking calculator. Raised and attached decks are structural, so have the design checked by your building department or a licensed contractor before work starts.