FINAL TOOLBOX
01 // Chart Studio02 // Visual Solvers03 // Calculators04 // Formulas05 // Unicode & Symbols
03 // Bidirectional STEM Calculators // EVERYDAYG = (A × C) / S_cov

Wall Paint Volume & Coat Coverage Calculator

Required architectural paint volume G equals net paintable wall surface area A multiplied by the number of finish coats C, divided by the single-coat spread coverage rate S_cov.

G = (A × C) / S_cov
Pick which value you want to calculate (or type into any field):Solving for: G (gal or L) — Paint Volume Required
Calculated

Total gallons (or liters) of paint needed

0.11,000.00
unit

Total wall area minus doors and windows

10100,000.00
unit

Number of coats applied (2 coats standard for full hide)

15
unit

350–400 ft²/gal (or 10 m²/L) on smooth primed drywall

51,000.00
unit
Calculated Result · Paint Volume Required (G (gal or L))
2.2857

Step-by-Step Calculation

01Canonical Law: G = (A × C) / S_cov
02Given Inputs (Base Units): A (ft² or m²) = 400, C (coats) = 2, S_cov = 350
03Solve for G (gal or L) (Paint Volume Required): G (gal or L) = 2.2857

Required architectural paint volume G equals net paintable wall surface area A multiplied by the number of finish coats C, divided by the single-coat spread coverage rate S_cov.

Real-World Reference Values

Smooth Primed Drywall (US Gallon)350 – 400 ft² / gal per coat

9.8 – 11.2 m² per Liter metric equivalent

Rough Stucco / Unprimed Masonry200 – 275 ft² / gal per coat

Porous substrates absorb 30%–40% more first-coat binder

Standard Door / Window Deduction-21 ft² per Door | -15 ft² per Window

Subtract openings from perimeter × ceiling height

20-Row Comparison Table

Paint Volume Required (G (gal or L)) · Net Paintable Wall Area (A (ft² or m²))

Wall Paint Volume & Coat Coverage Calculator — Net Paintable Wall Area → Paint Volume Required
#Net Paintable Wall Area (A (ft² or m²))Paint Volume Required (G (gal or L))Δ %
0110 0.057143 -97.50%
02400 Current2.2857 0.00%
031,498.28 8.5616 +274.57%
042,242.41 12.8138 +460.60%
052,986.55 17.066 +646.64%
063,730.69 21.3182 +832.67%
074,474.83 25.5705 +1018.71%
085,218.97 29.8227 +1204.74%
095,963.11 34.0749 +1390.78%
106,707.24 38.3271 +1576.81%
117,451.38 42.5793 +1762.85%
128,195.52 46.8315 +1948.88%
138,939.66 51.0838 +2134.91%
149,683.80 55.336 +2320.95%
1510,427.93 59.5882 +2506.98%
1611,172.07 63.8404 +2693.02%
1711,916.21 68.0926 +2879.05%
1812,660.35 72.3448 +3065.09%
1913,404.49 76.5971 +3251.12%
2014,148.63 80.8493 +3437.16%
Was this tool helpful?

Frequently Asked Questions

How do I calculate net wall area A for a rectangular room?+

Multiply room perimeter 2 × (Length + Width) by ceiling height, then subtract 21 sq ft per door and 15 sq ft per standard window.

Can I use this calculator in Square Meters (m²) and Liters (L)?+

Yes. Enter A in m² and set Spread Rate S_cov to ~10 m²/L; the solved output G will be in Liters.

How much extra paint should I buy for touch-ups and roller absorption?+

Round up to the next whole gallon/liter container and add 10% waste margin for textured walls.