Paint Coverage Converter: Gallons & Liters Spreading Rates
Use this paint coverage converter to convert manufacturer paint spreading rates between North American units (sq ft per gallon) and international metric units (sq m per liter). Includes substrate porosity allowances for raw drywall, stucco, and textured masonry.
Buy 6 gallons (1 × 5-gallon pail + 1 single gallon) for 2 coats over 650 sq ft (10% roller waste). Metric: 19.7 Liters.
| Surface Wall & Ceiling Area | 650 sq ft |
|---|---|
| Wall Substrate Profile | Medium Knockdown Texture |
| Spreading Rate (Imperial) | 275 sq ft per US gallon |
| Spreading Rate (Metric) | 6.75 sq m per liter |
| Finish Coats Required | 2 coats |
| Total Effective Coverage Needed | 1,430 sq ft (132.9 sq m) |
| US Liquid Gallons Needed | 5.20 gal (Buy: 6 gal) |
| Metric Liters Needed | 19.68 liters |
How to Measure for Paint Coverage Converter
- Measure net wall and ceiling surface area in square feet or square meters, subtracting large windows and doorways.
- Check the technical data sheet (TDS) on your paint can for the manufacturer recommended spreading rate (typically 350–400 sq ft/gal on smooth drywall).
- Select your wall substrate condition (previously painted smooth drywall, orange-peel texture, unprimed masonry, or rough exterior stucco).
- Factor in two finish coats for full color saturation, plus an initial sealing primer coat on raw drywall or color transitions.
How the Calculation Works
The mathematical conversion between sq ft per gallon and sq m per liter relies on US gallon volume (3.78541 liters) and square footage (1 sq m = 10.7639 sq ft). The conversion formula is: `(Sq Ft / Gallon) × 0.02454 = Sq M / Liter`. Conversely, `(Sq M / Liter) × 40.745 = Sq Ft / Gallon`. For material requirements, total area is divided by spreading rate and multiplied by the number of coats, with a 10% roller nap retention and cutting-in allowance.
- Gross area per coat = 650 sq ft. Two coats = 1,300 sq ft. With 10% waste = 1,430 sq ft. Gallons needed = 1,430 / 300 = 4.77 gallons. Round up to 5 whole gallons (or 1 five-gallon bucket). Metric equivalent = 18.05 liters (4.45 sq m/L spreading rate).
Paint Coverage Converter Reference & Specifications
| Wall Substrate & Texture | Coverage (Sq Ft / Gallon) | Coverage (Sq M / Liter) | Recommended Roller Nap |
|---|---|---|---|
| Smooth Previously-Painted Drywall | 350 – 400 sq ft/gal | 8.6 – 9.8 sq m/L | 3/8" Microfiber Nap |
| Light Texture (Orange Peel) | 300 – 350 sq ft/gal | 7.4 – 8.6 sq m/L | 1/2" Knit or Microfiber |
| Medium Texture (Knockdown) | 250 – 300 sq ft/gal | 6.1 – 7.4 sq m/L | 1/2" – 3/4" High-Density Nap |
| Heavy Texture (Popcorn / Skip Trowel) | 200 – 250 sq ft/gal | 4.9 – 6.1 sq m/L | 3/4" Extra-Thick Nap |
| Raw Unprimed Drywall (High Absorption) | 250 – 300 sq ft/gal | 6.1 – 7.4 sq m/L | PVA Sealing Primer First |
| Exterior Masonry / Stucco (Rough) | 150 – 200 sq ft/gal | 3.7 – 4.9 sq m/L | 1" – 1-1/4" Slump Roller Nap |
Frequently Asked Questions About Paint Coverage Converter
How many square meters does one liter of paint cover?
On standard smooth drywall, one liter of quality latex paint covers approximately 8.5 to 10 square meters per coat (equivalent to 350 to 400 sq ft per US gallon). Porous surfaces like unprimed plaster or textured masonry will absorb more, reducing coverage to 5 to 7 sq m/liter.
What is the formula to convert sq ft per gallon to sq m per liter?
Multiply the square feet per gallon figure by 0.024542. For example, standard 350 sq ft/gal × 0.024542 = 8.59 sq m/liter. To convert back, multiply sq m/liter by 40.745.
Do I always need two coats of paint?
Yes, almost every paint manufacturer specifies two coats for true color development, washability, and uniform sheen. Even "one-coat coverage" paints only achieve single-coat hide over similar colors and pre-primed, perfectly smooth substrates.
How much paint does raw drywall soak up without primer?
Raw drywall face paper and joint compound soak up 20% to 40% more paint than pre-primed walls, which can ruin the finish with uneven "flashing" sheen spots. Applying an inexpensive PVA drywall primer first seals the surface so your premium topcoat achieves full 350–400 sq ft/gal coverage.
Is a UK/Imperial gallon the same as a US gallon for paint?
No. A US liquid gallon is 3.785 liters, while a British Imperial gallon is 4.546 liters (about 20% larger). North American paint cans are manufactured in US gallons (3.785 L), while European and UK paint is packaged in metric 1L, 2.5L, 5L, or 10L containers.