Deck Material Calculator: Boards, Framing, Footings & Hardware

Tell us your deck. Get the whole shopping list: joists, beams, posts, footings, hangers and fasteners, grouped by store aisle and ready to print.

PopularDeckConcreteFence
Deck boards to buy
30
composite boards, 16 ft

16 ft × 12 ft deck, 192 sq ft, 2×10 joists at 16 in o.c. Full list: 23 lines.

13Joists (2×10 × 12 ft)
46×6 posts
13Joist hangers
Lumber & deckingQty
Composite deck boards5.5 in × 16 ft, incl. 10% planning allowance30 pcs
Pressure-treated field joists2×10 × 12 ft · 16 in o.c.11 pcs
Built-up pressure-treated beam plies2–2×8 × 16 ft2 pcs
Pressure-treated support posts6×6 · field-cut after footing and beam elevations are confirmed4 pcs
Hardware & concreteQty
Hidden deck fasteners90-count universal fastener box4 boxes
Ledger flashingCorrosion-resistant, compatible with treated lumber16 ft
Concrete mix60 lb bags · 0.45 cu ft published yieldConfirm
Price this deck

Your deck

Decking
Support layout
Board layout
More options (5)(4)
Board layout (more options)

The list rebuilds as you change any field

How it’s calculated

Joists: 16 ft × 12 ÷ 16 in o.c. = 12 bays → 13 lines (11 field + 2 rim)

Joist size: 12 ft span → 2×10 (2021 IRC Southern Pine span table)

Boards: 192 sq ft ÷ 7.3 sq ft = 26.3 → 27; +10%, rounded up → 30 × 16 ft

Footing depth depends on your local frost line, so concrete stays “Confirm” until you enter it.

Displayed measurements are rounded; calculations use full precision.

Warnings & assumptions

This is a prescriptive planning takeoff, not a permit design. Confirm local amendments, frost depth, soil, connectors and inspection requirements.

The IRC table selection assumes a simple rectangular residential deck at 40 psf live load. Snow drift, hot tubs, roofs and unusual loads require project-specific design.

Concrete and form-tube quantities remain open until the local frost-protected footing depth is entered.

Do not attach a ledger until the wall assembly, flashing and approved fastening schedule are verified.

Deck size: 16 × 12 ft (user)

The first dimension runs parallel to the house/outer beam; the second is the joist span.

Support layout: House ledger + outer beam (user)

This choice controls beam, post, hanger and ledger quantities.

2021 IRC §R507 and Tables R507.3.1, R507.4, R507.5(1), R507.6, R507.7 (https://codes.iccsafe.org/content/IRC2021P1/chapter-5-floors)

Decking: Composite (user)

The selected surface material controls stock coverage and fasteners.

TimberTech Composite Decking Installation Guide, pp. 3–4 (https://assets.timbertech.com/content/dam/wp-content/TimberTech-Composite-Decking-Installation-Guide_ENG.pdf)

Joist spacing: 16 in o.c. (derived)

Composite boards installed perpendicular to joists allow 16 in o.c. maximum; the engine tightens spacing when the IRC span table requires it.

TimberTech Composite Decking Installation Guide, pp. 3–4 (https://assets.timbertech.com/content/dam/wp-content/TimberTech-Composite-Decking-Installation-Guide_ENG.pdf)

Framing design basis: Southern Pine No. 2 · 2×10 joists · 2–2×8 beam (derived)

Sizes are selected directly from the 2021 IRC prescriptive deck tables at 40 psf live load, without interpolation.

2021 IRC §R507 and Tables R507.3.1, R507.4, R507.5(1), R507.6, R507.7 (https://codes.iccsafe.org/content/IRC2021P1/chapter-5-floors)

Soil bearing: 1,500 psf (default)

1,500 psf is the conservative IRC presumptive value for clay, sandy clay, silty clay and clayey silt. Local soil conditions can require engineering.

2021 IRC Table R401.4.1 (https://codes.iccsafe.org/content/IRC2021V3.0/chapter-4-foundations)

Footing depth: Confirm local frost depth (needs-confirmation)

IRC requires attached-deck footings to be frost protected. The local frost line is not derivable from deck dimensions.

2021 IRC §R507 and Tables R507.3.1, R507.4, R507.5(1), R507.6, R507.7 (https://codes.iccsafe.org/content/IRC2021P1/chapter-5-floors)

Deck-board allowance: 10% (default)

Manufacturer planning guidance recommends extra boards for cuts and unusable off-cuts; patterned layouts need more.

TimberTech, How to Calculate How Much Decking You Need (https://www.timbertech.com/ideas/how-to-calculate-how-much-decking-you-need/)

Deck height: 24 in above grade (user)

Walking-surface height controls whether a guard is required and affects field-cut post lengths.

2021 IRC §R312.1.1–R312.1.2 (https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning)

Guard / railing: Not included (derived)

IRC requires a guard where the walking surface is more than 30 in above floor or grade within 36 in horizontally.

2021 IRC §R312.1.1–R312.1.2 (https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning)

Shopping list (top lines of 23)Qty
Composite deck boards5.5 in × 16 ft, incl. 10% planning allowance30 pcs
Pressure-treated field joists2×10 × 12 ft · 16 in o.c.11 pcs
Pressure-treated support posts6×6 · field-cut after footing and beam elevations are confirmed4 pcs
Joist hangersFor 2×10 joists · corrosion-resistant13 ea
Hidden deck fasteners90-count universal fastener box4 boxes
Concrete mix60 lb bags · 0.45 cu ft published yieldConfirm
Price this deck

How it’s calculated

Joists: 16 ft × 12 ÷ 16 in o.c. = 12 bays → 13 lines (11 field + 2 rim)

Joist size: 12 ft span → 2×10 (2021 IRC Southern Pine span table)

Boards: 192 sq ft ÷ 7.3 sq ft = 26.3 → 27; +10%, rounded up → 30 × 16 ft

Footing depth depends on your local frost line, so concrete stays “Confirm” until you enter it.

Displayed measurements are rounded; calculations use full precision.

Warnings & assumptions

This is a prescriptive planning takeoff, not a permit design. Confirm local amendments, frost depth, soil, connectors and inspection requirements.

The IRC table selection assumes a simple rectangular residential deck at 40 psf live load. Snow drift, hot tubs, roofs and unusual loads require project-specific design.

Concrete and form-tube quantities remain open until the local frost-protected footing depth is entered.

Do not attach a ledger until the wall assembly, flashing and approved fastening schedule are verified.

Deck size: 16 × 12 ft (user)

The first dimension runs parallel to the house/outer beam; the second is the joist span.

Support layout: House ledger + outer beam (user)

This choice controls beam, post, hanger and ledger quantities.

2021 IRC §R507 and Tables R507.3.1, R507.4, R507.5(1), R507.6, R507.7 (https://codes.iccsafe.org/content/IRC2021P1/chapter-5-floors)

Decking: Composite (user)

The selected surface material controls stock coverage and fasteners.

TimberTech Composite Decking Installation Guide, pp. 3–4 (https://assets.timbertech.com/content/dam/wp-content/TimberTech-Composite-Decking-Installation-Guide_ENG.pdf)

Joist spacing: 16 in o.c. (derived)

Composite boards installed perpendicular to joists allow 16 in o.c. maximum; the engine tightens spacing when the IRC span table requires it.

TimberTech Composite Decking Installation Guide, pp. 3–4 (https://assets.timbertech.com/content/dam/wp-content/TimberTech-Composite-Decking-Installation-Guide_ENG.pdf)

Framing design basis: Southern Pine No. 2 · 2×10 joists · 2–2×8 beam (derived)

Sizes are selected directly from the 2021 IRC prescriptive deck tables at 40 psf live load, without interpolation.

2021 IRC §R507 and Tables R507.3.1, R507.4, R507.5(1), R507.6, R507.7 (https://codes.iccsafe.org/content/IRC2021P1/chapter-5-floors)

Soil bearing: 1,500 psf (default)

1,500 psf is the conservative IRC presumptive value for clay, sandy clay, silty clay and clayey silt. Local soil conditions can require engineering.

2021 IRC Table R401.4.1 (https://codes.iccsafe.org/content/IRC2021V3.0/chapter-4-foundations)

Footing depth: Confirm local frost depth (needs-confirmation)

IRC requires attached-deck footings to be frost protected. The local frost line is not derivable from deck dimensions.

2021 IRC §R507 and Tables R507.3.1, R507.4, R507.5(1), R507.6, R507.7 (https://codes.iccsafe.org/content/IRC2021P1/chapter-5-floors)

Deck-board allowance: 10% (default)

Manufacturer planning guidance recommends extra boards for cuts and unusable off-cuts; patterned layouts need more.

TimberTech, How to Calculate How Much Decking You Need (https://www.timbertech.com/ideas/how-to-calculate-how-much-decking-you-need/)

Deck height: 24 in above grade (user)

Walking-surface height controls whether a guard is required and affects field-cut post lengths.

2021 IRC §R312.1.1–R312.1.2 (https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning)

Guard / railing: Not included (derived)

IRC requires a guard where the walking surface is more than 30 in above floor or grade within 36 in horizontally.

2021 IRC §R312.1.1–R312.1.2 (https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning)

Complete shopping list · 23 lines

Your whole shopping list

16 ft × 12 ft deck · Verify local code before purchase.

Lumber & Decking

  • Composite deck boards5.5 in × 16 ftIncludes 10% planning allowance after manufacturer board-coverage rounding.
    30 pcs
  • Pressure-treated field joists2×10 × 12 ft · 16 in o.c.13 total joist lines including two side/rim joists.
    11 pcs
  • Pressure-treated side rim joists2×10 × 12 ft
    2 pcs
  • Front rim board2×10 × 16 ft
    1 pcs
  • Pressure-treated ledger2×10 × 16 ftInstall only after confirming the existing wall is ledger-compatible.
    1 pcs
  • Built-up pressure-treated beam plies2–2×8 × 16 ft1 beam line; posts at 5.33 ft maximum actual spacing.
    2 pcs
  • Joist blocking2×10 cut to fit1 row; use suitable framing off-cuts first.
    12 pcs
  • Pressure-treated support posts6×6 · field-cut after footing and beam elevations are confirmedIRC prescriptive 6×6 post; the engine does not invent a stock length from deck height alone.Confirm: Verify footing-top and beam elevation before choosing post stock length.
    4 pcs
  • Composite fascia boards12 ft manufacturer stockCovers the front and two exposed sides; seam layout may change the final cut plan.
    4 pcs

Hardware & Waterproofing

  • Hidden deck fasteners90-count universal fastener box50 sq ft planning coverage per box at 16 in o.c.
    4 boxes
  • Joist hangersFor 2×10 joists · corrosion-resistantUse the connector manufacturer's specified hanger fasteners.
    13 ea
  • Ledger flashingCorrosion-resistant, compatible with treated lumberIRC requires corrosion-resistant flashing at the ledger.
    16 ft
  • Ledger structural fastenersType and spacing must match the verified wall assemblyDeck size alone is not enough to select an IRC ledger fastening schedule.Confirm: Confirm rim-board material, sheathing thickness and approved fastener schedule before purchase.
    Confirm
  • Rim-to-joist structural screwsNo. 10 × 3 in wood screwsThree per joist end at each calculated rim board.
    39 ea
  • Post bases6×6, corrosion-resistant, approved for treated lumber
    4 ea
  • Post-to-beam caps6×6 post to 2–2×8 built-up beamSelect a listed connector that matches the final beam/post detail.
    4 ea
  • Built-up beam nails10d (3 in × 0.128 in), hot-dip galvanizedTwo rows at each edge, 16 in o.c., for every ply interface.
    48 ea
  • Joist and ledger waterproofing tape1-5/8 in × 50 ft rollsCovers joists, blocking, rim boards and ledger; 204 linear ft takeoff.
    5 rolls
  • Beam waterproofing tape3-1/8 in × 50 ft rollsCovers 1 built-up beam line.
    1 rolls

Concrete & Site

  • 12 in round concrete form tubesLength pending local frost depth4 footing locations; 12 in pier is at least twice the nominal 6 in post width.Confirm: Enter the locally required footing depth to calculate tube and concrete quantities.
    Confirm
  • Round footing bearing pads16 in diameter × 6 in thick minimumIRC table row up to 40 sq ft tributary area at 1,500 psf soil bearing.
    4 ea
  • Concrete mix60 lb bags · 0.45 cu ft published yield4 footing locations; quantity intentionally withheld until frost depth is known.Confirm: Enter the locally required footing depth before buying concrete.
    Confirm
  • Compacted gravel base6 in base under each footingQUIKRETE footing guide specifies a 6 in gravel base; bag count depends on the selected aggregate product.
    2.79 cu ft

This is a prescriptive planning takeoff, not a permit design. Confirm local amendments, frost depth, soil, connectors and inspection requirements.

The IRC table selection assumes a simple rectangular residential deck at 40 psf live load. Snow drift, hot tubs, roofs and unusual loads require project-specific design.

Concrete and form-tube quantities remain open until the local frost-protected footing depth is entered.

Do not attach a ledger until the wall assembly, flashing and approved fastening schedule are verified.

Edit the project basis to save your calculation.

All calculators

D
Deck material calculatorBoards, joists, beams, posts, footings, hangers, fasteners.
C
Concrete calculatorBags, volume, gravel base, form boards for a slab.
F
Fence calculatorPosts, rails, pickets and hardware.
P
Fence picket calculatorPickets, rails, posts and screws, board by board.
B
Fence post concrete calculatorBags per post and for the whole fence.
H
Fence post depthHole depth, post length to buy, frost override.
S
Deck stair calculatorRisers, treads, stringers and landing pad.
T
Sonotube calculatorConcrete bags for round tube forms.

Cost estimates on pricetobuild

Deck costConcrete slab costFence costDriveway costRetaining wall costPaver patio cost

Why this list goes past deck boards

Surface-board calculators answer the easiest question and leave the expensive structure behind. This takeoff starts with the same dimensions, then follows the load path: decking to joists, joists to beams, beams to posts, and posts to footing pads. Hardware and waterproofing sit beside the member they protect. Once the list is complete, you can estimate what this deck will cost with editable prices.

Spacing is a product rule and a span rule

Composite boards installed straight can sit on joists at 16 in o.c.; diagonal layouts tighten that to 12 in o.c.. That spacing determines the number of joists. Joist depth is a separate lookup against the verified IRC span table—so a 12 ft span does not get rounded down to a convenient 2×8.

Why footing depth stays open

The deck dimensions determine tributary area and a prescriptive bearing-pad size. They do not reveal the local frost line. Until that local value is entered, concrete and tube quantities remain marked “confirm” instead of becoming a confident-looking guess. For slab pads around the deck, use the concrete slab calculator. Once the depth is known, size tube footings with the sonotube calculator and lay out steps with the deck stair calculator. Fence posts follow a different rule: fence post depth.

Questions before the lumber run

What does this deck material calculator include?

It calculates the surface boards and the framing and site materials people commonly miss: joists, rim boards, beams, posts, footing pads, form tubes, concrete, connectors, flashing, fasteners, waterproofing tape and fascia.

How far apart should deck joists be?

For the composite system used here, straight boards are limited to 16 inches on center and diagonal boards to 12 inches on center. The joist size is then selected from the 2021 IRC Southern Pine span table.

How deep should deck footings be?

The correct depth depends on the local frost line and code amendments. This calculator does not guess it. Enter the locally required depth to unlock the concrete and form-tube quantities.

Can I use the list without creating an account?

Yes. The complete result is visible, printable and checkable without signup, an email gate, a paywall or a watermark.