How big is an 8-foot hexagon deck?

An 8′-side hexagon has 166 sqft area, 48′ perimeter, 13.9′ flat-to-flat, and exactly 16′ vertex-to-vertex (always 2·s for a regular hexagon). This is a popular gazebo-deck size — fits a 6-person hot tub centered with 2′ clearance, or 6-chair patio dining set with center umbrella.

How much does a hexagon deck cost?

$30-55 per square foot installed depending on surface, height, and railing. An 8′-side hexagon (166 sqft) in composite mid-tier with 36″ railing: $6,000-9,500. Same footprint in PT pine without railing: $4,000-6,500. Hexagons cost ~15-20% more than the same square-footage rectangle (vs +25-35% for octagon, +35-60% for round) — they're the cheapest geometric shape.

Why is a hexagon cheaper than an octagon or round deck?

Three reasons: (1) Only 6 mitre cuts per row vs 8 (octagon) or 12-32 (round); (2) Decking waste 13-18% vs 15-20% (octagon) or 25-28% (round) — fewer angled edge cuts; (3) Standard 30° mitre angle is on every chop saw — DIY-friendly. The trade-off: hexagons look 'less round' than octagons, which matters if the aesthetic is the goal.

How do you frame a hexagon deck?

Orient the hexagon with two flat sides on top + bottom. Build a rectangular outer joist frame whose width = s·√3 (flat-to-flat) and length = 2·s (vertex-to-vertex). Run joists at 16″ o.c. across the flat-to-flat dimension. Cut each joist to its hexagonal chord — center joist spans the full vertex-to-vertex (2·s); outermost joists are short (= s). 6 corner posts (one per vertex) + doubled-2×10 perimeter beam under the rim. Optional center post for spans >14′ flat-to-flat.

How many posts does a hexagon deck need?

6 posts at minimum — one at each vertex of the hexagon (where two sides meet at 120°). 6×6 PT recommended for spans >10′ flat-to-flat; 4×4 works for small gazebos under 10′ flat-to-flat with no railing. Above 14′ flat-to-flat, add a 7th center post — DeckMath auto-flags this when your dimensions exceed the threshold.

What size joists for a hexagon deck?

Use 2×10 PT joists for hexagons up to 14′ flat-to-flat (no center post). Use 2×12 PT or add a center post for 14-18′ flat-to-flat. Joist spacing is 16″ o.c. for PT/composite; 12″ o.c. for Ipe or hidden-fastener composite. The center joist on the vertex-to-vertex axis spans 2·s — this is the longest joist and determines lumber stock length (8′-side hexagon needs 16′ joist stock).

Can you put a hot tub on a hexagon deck?

Yes — hexagon decks are a popular hot-tub footprint because the 6-sided shape mirrors many hot-tub corners. Use the Hot Tub Deck Calculator for reinforcement: a typical 7×7 hot tub (~5,000 lb filled) on an 8′-side hexagon (166 sqft) needs 12″ o.c. joist spacing under the tub footprint + 14″ Ø footings under the 4 nearest perimeter posts. Total deck rating: 100 psf live load (vs 50 psf normal) under the tub zone.

What's the best material for a hexagon deck?

Composite mid-tier (Trex Enhance, $3.80/lf, 14% waste) is the best value — lowest waste, hides 30° mitre imperfections, 25-yr warranty, color-matched fascia trim wraps the 6 segments cleanly. Cedar is the gazebo classic look — the hexagon is a 100-year-old gazebo footprint, and cedar matches that aesthetic. PT pine is cheapest but every 30° angled cut needs annual stain. Ipe is overkill for a hexagon — the predrill labor savings only matter on rounds, not hexagons.

Hexagon vs octagon — which deck shape is better?

Hexagon: 15-20% cheaper, easier DIY, classic gazebo look, but visibly less round. Octagon: more circular aesthetic, 25-35% premium over rectangle, mid-difficulty DIY, more posts (8 vs 6). If you want gazebo vibes + DIY-doable, hexagon. If you want the deck to read as 'almost-round' at a glance, octagon. If you want truly round, use the Round Deck Calculator (24+ facets).

6-sided · gazebo footprint · DIY-friendly

Hexagon Deck Calculator

Q: Is a hexagon deck DIY-friendly?

Yes — hexagons are the most DIY-friendly geometric deck. Only 6 mitre cuts at 30° each (standard chop-saw setting), 6 corner posts laid out from a center point with a string compass, and decking that runs parallel to any pair of opposing sides. Intermediate DIY: 2-4 weekends for a 6-8′ side hexagon. Beginner DIY: doable if you've built one rectangular deck before. Compare: octagons are marginal-DIY (8 mitres), rounds are pro-only.

Size a regular 6-sided deck — the classic gazebo footprint. Area = (3√3/2)·s². The simplest geometric shape: only 6 mitred rim segments at 30°, 6 vertex posts, and decking that runs parallel to any pair of opposing sides. DeckMath returns flat-to-flat, vertex-to-vertex, chord-joist count, posts + footings, 13-18% decking waste — lowest of the geometric shapes.

6 equal sides · 120° angles5 surface optionsChord joists30° mitre rimDIY-friendly

6·Equal sides

120°·Interior angle

6+1·Posts (+ center)

16″·Joist o.c.

Inputs

Hexagon dimensions

Side lengthlength of one side (6 equal sides)

Area

127 sqft

Flat-to-flat

12.12′

Corner-to-corner

14′

Height off gradeabove 30″ triggers IRC R312 railing

Surface material

Post size6×6 above 10′ flat

State2-letter

Scope

Hexagon Deck · Composite mid-tier (Trex Enhance)·Northeast

$9,323 – $11,989$73–$94 /sq ft installed

12.12′ flat · 127 sqft6 6x6 posts · 6 footings10 chord joists @ 16″ o.c.

Area

6 × 7′ sides

Flat-to-flat

Corner-to-corner 14′

Materials

Low $2,887

Labor

1.22× region · ~1.25× hexagon

Compliance · IRC + framing notes

No guardrail required — 24″ off grade < 30″

IRC R312

Under 30″ off grade, IRC R312 does not mandate a guardrail. Hexagon gazebo decks at gazebo-deck height (12-24″) often skip the railing for an open gazebo aesthetic.

Chord joists — 10 joists at 16″ o.c. (102 lf total)

IRC R507.6 + AWC DCA-6

Joists run parallel across flat-to-flat (12.12′). Center joist spans full vertex-to-vertex (14′ = 2·s); outermost joists are shortest (= s = 7′ at the very flat edges). Total 102 lf — ~73% of full-length joist stock.

6 corner posts only — no center post needed (12.12′ flat-to-flat ≤ 14′)

IRC R507.5 + DCA-6

Hexagons under 14′ flat-to-flat are framed with corner posts only (one per vertex). 2×10 PT joists span the full flat-to-flat at 16″ o.c. without intermediate support.

Decking waste — 14% (30° mitre cuts)

Industry standard waste %

Hexagons waste 13-18% of decking — between rectangle (7-10%) and octagon (15-20%), much lower than round (25-28%). Only 6 mitre cuts per row, all at 30° (standard chop-saw setting). Composite hides 30° mitre imperfections cleanly — lowest waste of the surface options.

Bill of materials

Item

Qty

Total

Decking — Composite mid-tier (Trex Enhance)

20 boards · 311 lf · 26 rows · 14% waste (30° mitre cuts)

Home Depot Lowe’s

20 board

$1,183

Decking — Composite mid-tier (Trex Enhance)

20 boards · 311 lf · 26 rows · 14% waste (30° mitre cuts)

Home Depot Lowe’s

20 board

—

$1,183

Concrete footings — 14″ Ø to frost depth

6 footings · one per vertex

6.0 footing

$570

Concrete footings — 14″ Ø to frost depth

6 footings · one per vertex

6.0 footing

—

$570

Floor joists — 2×10 PT (variable chord lengths)

10 joists · 102 lf · 16″ o.c. · cut to hexagon chords

10 joist

$315

Floor joists — 2×10 PT (variable chord lengths)

10 joists · 102 lf · 16″ o.c. · cut to hexagon chords

10 joist

—

$315

6x6 PT posts

6 corner (one per vertex)

6.0 post

$312

6x6 PT posts

6 corner (one per vertex)

6.0 post

—

$312

Doubled 2×10 PT perimeter beams (under rim)

6 segments doubled · 84 lf total

6.0 segment

$260

Doubled 2×10 PT perimeter beams (under rim)

6 segments doubled · 84 lf total

6.0 segment

—

$260

Post anchors (ABU) + joist hangers (LUS210)

6 ABU66Z · 20 LUS210 (2× per joist)

26 pc

$220

Post anchors (ABU) + joist hangers (LUS210)

6 ABU66Z · 20 LUS210 (2× per joist)

26 pc

—

$220

Perimeter rim — 6 mitred segments (2×10 PT)

6 × 7′ segments at 30° mitres · 42 lf

6.0 segment

$137

Perimeter rim — 6 mitred segments (2×10 PT)

6 × 7′ segments at 30° mitres · 42 lf

6.0 segment

—

$137

Hidden fastener clips + edge screws

127 sqft × $0.85/sqft

1,528 pc

$108

Hidden fastener clips + edge screws

127 sqft × $0.85/sqft

1,528 pc

—

$108

Materials subtotal

$3,105

Hexagon deck pricing 2026-Q1. 14% decking waste baked in (30° mitre premium — lowest of the geometric shapes). Labor 1.22× regional × ~1.25× hexagon.

Regular hexagon = 6 equal sides at 120° interior angles. Area = (3√3/2)·s². Most DIY-friendly geometric deck — only 6 mitres at 30° each. Engineer review recommended above 16′ flat-to-flat.

How to use

Three steps. Permit-ready output.

Set side length

Side length (s) is the length of ONE hexagon side. s=7′ → 12.1′ flat-to-flat, 14′ vertex-to-vertex, 127 sqft. s=10′ → 17.3′ flat-to-flat, 20′ vertex-to-vertex, 260 sqft. Most hexagon decks use 6-10′ sides — the size of a standard gazebo footprint.

Pick height + railing

Above 30″ off grade triggers IRC R312 — 36″ guardrail around all 6 segments. Hexagon rail joints are at 60° exterior angles (120° interior) — every cap-rail system sells 60° or 30° corner connectors off-the-shelf.

Pick surface material

PT pine ($1.95/lf — cheapest, 16% waste), cedar ($3.40/lf — gazebo classic, 18% waste, stainless screws req), composite mid Trex Enhance ($3.80/lf — best value, 14% waste), composite premium Trex Transcend ($5.40/lf — premium, 13% waste), Ipe ($7.80/lf — 50-yr hardwood, 18% waste).

Post size + center post

6×6 PT at all 6 vertices for spans >10′ flat-to-flat. 4×4 works for small hex decks under 10′ flat-to-flat with no railing. Above 14′ flat-to-flat, add a center support post to halve the joist span — DeckMath auto-flags this.

Read your hexagon deck cost

Project total, $/sqft, area, perimeter, flat-to-flat + vertex-to-vertex dimensions, post + joist + footing counts, BoM, share link, PDF/CSV export.

How we calculate

The math, fully transparent.

The Hexagon Deck Calculator sizes a regular 6-sided deck — the classic gazebo footprint with 120° interior angles. The simplest of the geometric deck shapes: only 6 mitred rim segments at 30°, 6 vertex posts, and decking that runs parallel to any pair of opposing sides. Pick side length (3–16′), height, surface, post size, and state. DeckMath returns area (using (3√3/2)·s²), flat-to-flat dimension, vertex-to-vertex span, chord-joist count, 6 corner posts + optional center, mitred-rim BoM, 13-18% decking waste (lower than octagon's 15-20%, much lower than round's 25-28%), and a 36″ railing line item when height exceeds 30″ (IRC R312). Labor premium is +15-40% vs rectangular — the lowest of any geometric shape because only 6 mitres are involved.

IRC references

IRC 2021 R507.6 — Joist span (chord joists size to longest chord = 2·s at vertex-to-vertex axis)
IRC 2021 R507.5 — Beam span (6-segment perimeter beam — each segment is one hexagon side)
IRC 2021 R507.3 — Footings at each of 6 vertices + optional center
IRC 2021 R312 — 36″ guardrail required ≥ 30″ off grade
AWC DCA-6 — Prescriptive deck framing (hexagon framing common; engineer review recommended above 16′ flat-to-flat)

Hexagon deck pricing 2026-Q1. Decking waste 13-18% (30° mitre premium — lowest of the geometric shapes). Labor 1.15-1.40× rectangular deck. Geometry coefficients exact: flat-to-flat = √3·s, area = (3√3/2)·s², vertex-to-vertex = 2·s.

Area

A = (3√3/2)·s² ≈ 2.598·s²

Regular hexagon area as a function of side length. s=6′ → 94 sqft. s=8′ → 166 sqft. s=10′ → 260 sqft.

Flat-to-flat

F = s·√3 ≈ 1.732·s

Distance across the hexagon between two parallel sides — the framing-square width. s=7′ → 12.1′ flat-to-flat. Use this dimension when ordering 14′ joists from the lumber yard (one length spans full flat-to-flat).

Vertex-to-vertex

V = 2·s

Distance across opposite corners — exactly twice the side length. s=7′ → 14′ corner-to-corner. The hexagon's longest dimension. Used for sizing the gazebo umbrella spread or the central skylight in a roofed hex.

Joist count

n = floor(F·12 / 16) + 1

Joists span across flat-to-flat at 16″ o.c., each cut to chord. Center joist runs through the vertex-to-vertex axis (longest at 2·s). Outermost joists are at the very flat edges (shortest at the side length itself = s). Total joist linear feet ~75-80% of square-frame full-length joists.

Decking waste

13-18% for hexagons

Lower than octagon (15-20%) or round (25-28%) because hexagons have only 6 mitre cuts per row of decking. Composite hides cuts best (13-14%); cedar + Ipe waste 18% from 30° mitre splintering.

Labor premium

1.15× to 1.40× rectangular labor

Lowest premium of any geometric shape. PT 1.15× (chord joists + 6 mitre cuts). Composite 1.25× (hidden fastener at mitred ends). Ipe 1.40× (predrill every angled fastener). DIY-friendly with a chop saw set to 30°.

Save your plan

Don’t lose this estimate.

Your inputs are preserved in the URL — email it to yourself or copy the link so you can compare with contractor bids later. No account needed.

Frequently asked

Questions, answered.

Embed this calculator

One line. Any site. Free.

Drop the snippet into your contractor site, blog, or marketing page. Theme matches the parent site automatically.

<!-- Drop into any HTML, WordPress, Webflow, or contractor site -->
<script src="https://embed.deckmath.com/v1.js"
        data-deckmath-calc="hexagon-deck-calculator"
        data-theme="auto"
        async></script>

Octagon Deck Calculator

Octagon (8-sided) deck cost + structural sizing. Area = 2(1+√2)·s². Chord joists, 22.5° mitred rim, 8 vertex posts, 15-20% decking waste, IRC R312/R507.

Round Deck Calculator

Round (circular) deck cost + structural sizing — faceted-polygon framing model (12/16/24/32 facets). 25-28% decking waste. Highest labor premium of any deck shape.

Deck Material Calculator

Calculate exact decking boards, joists, beams, posts, footings, and fasteners for your deck — IRC 2021 compliant.

Hexagon Deck Calculator

Inputs

Compliance · IRC + framing notes

No guardrail required — 24″ off grade < 30″

Chord joists — 10 joists at 16″ o.c. (102 lf total)

6 corner posts only — no center post needed (12.12′ flat-to-flat ≤ 14′)

Decking waste — 14% (30° mitre cuts)

Bill of materials

Three steps. Permit-ready output.

Set side length

Pick height + railing

Pick surface material

Post size + center post

Read your hexagon deck cost

The math, fully transparent.

IRC references

Don’t lose this estimate.

Questions, answered.

One line. Any site. Free.

More calculators you'll need.

Octagon Deck Calculator

Round Deck Calculator

Deck Material Calculator