DeckMath
5 paint types · 5 conditions · paint-vs-stain TCO · DIY + contractor

Deck Paint Calculator

Compute exact gallons of paint, primer, and supplies plus total installed cost for painting a deck. 5 deck-paint product types — 100% acrylic porch & floor (Behr Premium, Sherwin Williams Porch & Floor, 7-yr lifespan), oil-modified alkyd (Benjamin Moore INSL-X Tough Shield, 8-yr lifespan), elastomeric coating (Rust-Oleum RockSolid, Behr DeckOver Max, 10-yr lifespan, 30% more material), solid-color stain (Olympic Maximum Solid, Cabot Solid Acrylic, 6-yr lifespan), and anti-slip textured (Sherwin Williams DeckShield with sand-grit additive, 8-yr lifespan for wet-zone walkways). Coverage formula accounts for first-coat penalty on rough/weathered/previously-stained wood (15-30% coverage reduction). Surface scope: deck-only, deck + rails + stairs, or deck + rails + stairs + skirting. 5 condition tiers drive prep cost. Includes paint-vs-stain 5-yr TCO comparison and a side-by-side ranking of all 5 paint-type options at the same scope.

5 paint productsPaint-vs-stain TCOPrimer math includedCondition-based coverage3 color tiersFree forever
5 products·Acrylic / oil / elastomeric / solid / anti-slip
$0.55-3.85/sqft·DIY material → contractor range
7-10 yr·Lifespan range
5-yr TCO·Paint vs 3 stain tiers

Inputs

Deck size + scope

sqft

ft

ea

ea

sqft

Total paint area725 sqft

Recoat existing paint. Scrape peeling spots + spot-prime + light sand. No full primer needed. Best-coverage scenario.

Install + region

Northeast · 1.22× labor

100% acrylic porch & floor

725 sqft · 2 coats · previously-painted · contractor · PA

Project total
$4,053 $5,094
$7/sqft · 8% contingency included · 7-yr lifespan
Northeast 1.22×8 gal + 3 gal primer

Gallons needed

First coat
4.5 gal
Coverage 161 sqft/gal
Recoats × 1
3.5 gal
240 sqft/gal each
Primer required: 3 gal @ $38/gal$114

Cost breakdown

Paint (8 gal × $52/gal)$416
Primer (3 gal)$114
Supplies (brush/roller/tray)$65
Prep (previously-painted)$471
Labor (Northeast 1.22×)$3,319
Subtotal (high)$4,717
Project total (high, +8% contingency)$5,094

5-year TCO: paint vs stain

Acrylic P&F paintCURRENT$4,574 · 7yr · 1× in 5yr
Transparent stain$2,166 · 2.5yr · 2× in 5yr
Semi-transparent stain$5,562 · 4yr · 2× in 5yr
Solid color stain$3,267 · 6yr · 1× in 5yr

Paint typically wins TCO on full deck + rails + skirting scope (vertical surfaces hold paint better). Stain wins on horizontal deck-only scope (penetrates instead of films). Numbers assume professional labor at current region.

Paint-type comparison (same scope)

Solid stainCHEAPEST$4,548 · $6.3/sqft
Acrylic P&FPICKED$5,094 · $7/sqft
Oil-alkyd$5,588 · $7.7/sqft
Anti-slip$7,188 · $9.9/sqft
Elastomeric$8,977 · $12.4/sqft

Recommendations

  • Acrylic P&F requires primer on previously painted (recoat scenario). Skipping primer compromises adhesion; recommend toggling primer on (adds ~$114 for ~3 gal).
  • Solid color stain (paint-like finish) is cheaper by $546 at this scope. Trade-off: 6-yr vs 7-yr lifespan, $48/gal vs $52/gal product cost.

Code + product references

  • EPA 40 CFR Part 745 — Lead-paint testing required before sanding/scraping pre-1978 painted surfaces
  • MPI 60 — Master Painters Institute deck-paint product spec (industry coverage standard)
  • ASTM D2486 — Scrub resistance test (verify paint rating)
  • Manufacturer specs — apply at 50-90°F surface temp, < 85% RH, no rain forecast 24 hr

How to use

Three steps. Permit-ready output.

  1. 01

    Enter deck sqft + surface scope

    Deck footprint sqft (top surface). Then choose scope: deck-only, deck + rails + stairs (adds railing LF × 7.5 sqft conversion + stair treads × 4.5 sqft + stringers), or deck + rails + stairs + skirting (adds vertical skirting sqft). Most deck-paint projects include the rails and stairs since paint exposed there ages faster than the deck surface.

  2. 02

    Pick wood condition tier

    5 tiers drive prep cost + coverage penalty. New PT MUST weather 6+ months first. Weathered gray = 1+ yr old PT, 15% coverage penalty. Previously stained = must strip or sand to bare wood. Previously painted = recoat scenario (best coverage, lowest prep). Rough mill = 30% coverage penalty (paint fills grain). Wrong condition selection causes paint failure within 1-3 yrs.

  3. 03

    Pick paint type + coats + color tier

    5 paint product types with documented coverage + lifespan + price. Coats: 1 (touch-up only), 2 (default for new paint), 3 (rough wood or color change). Color tier: standard (basic colors), premium (+18%), custom-match (+35%). Premium colors often cost more from the manufacturer + require minimum-order batches.

  4. 04

    Primer toggle + installer mode

    Primer required on bare wood for most paint types (auto-toggled on by condition). Skip primer ONLY on recoat-existing-paint scenarios with same paint type. Installer mode: DIY (hides labor, shows hours estimate + opportunity cost at $35/hr), or contractor (full labor billed by regional multiplier).

  5. 05

    Read paint vs stain comparison

    5-yr TCO panel surfaces paint vs 3 stain alternatives (transparent / semi-transparent / solid) at same scope. Paint lifespan 7-10 yrs (1 recoat in 5 yrs). Stain lifespan 2-6 yrs (2-3 recoats in 5 yrs). Paint typically wins 5-yr TCO when scope is rails + stairs + skirting because vertical surfaces hold paint better than stain.

How we calculate

The math, fully transparent.

The Deck Paint Calculator computes gallons of paint, primer, and supplies plus total installed cost (DIY or contractor) for painting a deck. 5 deck-paint product types — 100% acrylic porch & floor (Behr Premium, Sherwin Williams Porch & Floor, 7-yr lifespan), oil-modified alkyd (Benjamin Moore INSL-X Tough Shield, 8-yr lifespan), elastomeric coating (Rust-Oleum RockSolid, Behr DeckOver Max, 10-yr lifespan, 30% more material), solid-color stain (Olympic Maximum Solid, Cabot Solid Acrylic, 6-yr lifespan), and anti-slip textured (Sherwin Williams DeckShield with sand-grit additive, 8-yr lifespan for wet-zone walkways). Coverage formula accounts for first-coat penalty on rough/weathered/previously-stained wood (15-30% coverage reduction). Surface scope: deck-only, deck + rails + stairs, or deck + rails + stairs + skirting. 5 condition tiers drive prep cost (power wash + sand + scrape + spot prime). Includes paint-vs-stain 5-yr TCO comparison and a side-by-side ranking of all 5 paint-type options at the same scope.

IRC references

  • EPA 40 CFR Part 745 — Lead-paint testing required before sanding/scraping pre-1978 painted surfaces
  • MPI 60 — Master Painters Institute deck-paint product spec (industry coverage standard)
  • ASTM D2486 — Scrub resistance test (verify paint rating)
  • Manufacturer specs — apply at 50-90°F surface temp, < 85% RH, no rain forecast 24 hr

2026-Q1 retail pricing — Home Depot / Lowe's / Sherwin Williams / Benjamin Moore / Behr. Acrylic P&F $52/gal. Oil-alkyd $65/gal. Elastomeric $78/gal. Solid stain $48/gal. Anti-slip textured $72/gal. Primer $38/gal at 250 sqft/gal. Coverage 75-200 sqft/gal first coat (× 1.30 on recoat). Pro labor $1.95-3.85/sqft. Regional multiplier (NE 1.22× / W 1.28× / S 0.92× / MW 1.00×). 8% contingency.

Gallons needed
firstCoatGallons = ceil(totalSqft / (coverage_first × condition_mult), 0.5); recoatGallons = ceil((totalSqft / coverage_recoat) × additional_coats, 0.5); totalGallons = first + recoat

First-coat coverage varies by paint type (75-200 sqft/gal): elastomeric 75 sqft/gal (thick), acrylic P&F 180, solid stain 200. Recoat coverage is 25-35% better (~240-270 sqft/gal). Condition multiplier reduces first-coat coverage: new PT 0.95×, weathered 0.85×, previously stained 0.90×, recoat 1.00×, rough mill 0.70×. Round UP to 0.5 gal — paint stores sell in 1, 2.5, 5 gal — odd-coverage purchases waste material.

Total surface area
totalSqft = deckSqft + (rails_LF × 7.5 + treads × 4.5 + sections × 12) [if scope includes] + skirting_sqft [if scope includes]

Railing LF × 7.5 sqft assumes 36″ tall guard with balusters painted both sides. Stair tread 1.5 ft × 3 ft = 4.5 sqft each. Stair section accounts for visible stringer + skirting at ~12 sqft per section. Skirting sqft entered separately (varies by deck height and scope). Total drives gallon math.

Prep cost
prepCost = totalSqft × prep_$/sqft (varies by condition tier)

Condition tier sets $/sqft for prep: new PT $0.35, weathered $0.55, previously stained $0.85 (strip required), previously painted $0.65 (scrape peeling spots + spot prime), rough mill $0.45. Prep includes power wash + sand + scrape + spot prime. Skipping prep is the #1 cause of paint failure within 18 months.

Labor (contractor)
labor = (paint_$/sqft + prep_$/sqft × 0.30) × totalSqft × coat_mult × region_mult

Paint $/sqft varies $1.95 (solid stain) to $3.85 (elastomeric — heavy material). Coat multiplier 1 + 0.60 per additional coat (recoats are faster than first). Region multiplier (NE 1.22× / W 1.28× / S 0.92× / MW 1.00×). Prep included at 30% of prep cost as labor share (rest is materials/disposal). 8% contingency on subtotal.

5-year TCO (paint vs stain)
tco_5yr = singleCycleCost × ceil(5 / lifespanYears)

Paint lifespan 7-10 yrs = 1 application per 5-yr horizon. Stain transparent 2.5 yr = 2 applications. Semi-transparent 4 yr = 2. Solid stain 6 yr = 1. Paint typically beats stain on 5-yr TCO for rails + stairs (vertical surfaces hold paint better). Stain wins on horizontal deck-only scope (penetrates instead of films).

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