Wood Stain Calculator

Unit system

Entry mode

Stain type preset

Presets set coverage below; you can override.

Coverage rate

ft² / gal

Coats

First coat coverage factor

% of base

Lower values mean heavier first coat.

Subsequent coat factor

% of base

Excluded area

ft²

Subtract masked windows, hardware, or fixtures.

Porosity increase

%

Dense 0–5, typical 10–20, weathered 20–30.

Application waste

%

Lost to tray, rags, overspray, absorption.

Method

Adds 0%, 3%, or 10% waste.

Orientation

Vertical adds 2% waste allowance.

Thinning rate (if allowed)

%

Only if manufacturer allows. Increases effective volume.

Optimization mode

Container prices (optional)

5 gal pail price

$

1 gal can price

$

1 qt can price

$

VOC and timing (optional)

VOC content

Ambient temperature

Relative humidity

%

Total area

ft²

Sum of all surfaces to stain.

Faces × coats + porosity + waste − thinning effect

Results

Surface area

200.00 ft²

18.58 m²

Required volume (net)

1.626 gal

6.16 L

Purchase & overage

1.750 gal purchased

0.47 L overage

Effective waste allowance

10.0%

Includes base, method, orientation

Suggested container mix (min overage)

5 gal pail: 0
1 gal can: 1
1 qt can: 3

Estimated cost

$0.00

Per-coat consumption

Coat	Volume (gal)	Volume (L)
1	0.904	3.42
2	0.723	2.74

VOC estimate

0.000 kg total

0.000 lb (0 g)

0.0 g/L content

Recommended recoat time

24 hours

Based on entered temperature and humidity

Approximate full cure

72 hours

Rule-of-thumb model; check data sheet

Example scenarios

Scenario	Area	Coats	Coverage	Porosity	Waste	Method	Thinning	Required
Deck boards small	200 ft²	2	350 ft²/gal	15%	10%	brush	0%	1.63 gal (6.2 L)
Fence pickets	320 ft²	1	300 ft²/gal	20%	10%	sprayer	0%	1.92 gal (7.3 L)
Door set	72 ft²	2	350 ft²/gal	5%	5%	roller	0%	0.52 gal (2.0 L)

Formula used

Per-coat coverage: First coat coverage = BaseCoverage × FirstFactor%; Subsequent coverage = BaseCoverage × SubsequentFactor%.

Net required volume = (Area ÷ Cov₁ + (Coats−1) × Area ÷ Cov₂) × (1 + Porosity%) × (1 + Waste%) ÷ (1 + Thinning%).

Area (total mode): entered total minus excluded area.

Area (board mode): sum of each board Faces × L × W + [Edges ? 2×(L+W)×T : 0] × count.

Conversions: 1 gal = 3.785 L; 1 ft² = 0.092903 m².

How to use this calculator

Choose unit system and entry mode.
Use presets or set base coverage, coats, and per-coat factors.
Enter porosity, waste, method, orientation, and any excluded area.
Optionally add thinning, container prices, VOC, temperature, and humidity.
Press Calculate to get volumes, container mix, cost, and timing.
Export with Download CSV or Download PDF.

Always follow product data sheets for prep, application, recoats, and thinning rules.

Coverage presets by stain type

Stain type	US coverage (ft²/gal)	Metric coverage (m²/L)	Notes
Transparent	400	9.8	Highest spread rate; lightest tint
Semi-transparent	350	8.6	Common for decks and fences
Solid color	300	7.4	Heavier body; hides grain
Gel / heavy-bodied	250	6.2	Best on verticals; reduced sag

Values are typical starting points; always verify with the product data sheet.

Suggested porosity and waste allowances

Wood condition	Porosity adder (%)	Base waste (%)	Method adder	Orientation adder
Dense hardwood (new)	0–5	5–8	Brush 0, Roller +3, Sprayer +10	Horizontal 0, Vertical +2
Softwood (new)	10–15	8–10	Brush 0, Roller +3, Sprayer +10	Horizontal 0, Vertical +2
Weathered / rough	20–30	10–15	Brush 0, Roller +3, Sprayer +10	Horizontal 0, Vertical +2
End grain, cut edges	25–40	10–15	Brush 0, Roller +3, Sprayer +10	Horizontal 0, Vertical +2

Use higher values for rough-sawn lumber or open-grain species and when spraying.