How do I use the coverage rate from a paint tin?

The coverage rate (also called spreading rate) on a paint tin tells you how far one litre spreads in one coat on a smooth, non-porous surface. It is printed as: • Metric: 'X m² per litre' or 'X m²/L' • US: 'X sq ft per gallon' How to use it: • Litres needed = Area × coats / coverage (m²/L) • Area coverable = Litres × coverage / coats Important caveats: 1. The tin figure assumes a smooth, sealed surface. Porous, rough, or textured surfaces will absorb 20–50% more paint. 2. The figure is for one coat. If you plan two coats, you need twice the paint. 3. Coverage figures are optimistic marketing — most professionals add 10% to their calculated quantity.

How many sq ft does 1 gallon of paint cover?

The standard US figure is 400 sq ft per gallon for one coat on a smooth, prepared surface. This equals approximately 10 m²/L. However, actual coverage varies: • Premium quality paint: 400–450 sq ft/gal • Standard emulsion: 350–400 sq ft/gal • Self-priming paint-and-primer: 250–350 sq ft/gal (lower because it's thicker) • Primer alone: 200–300 sq ft/gal • Masonry paint: 100–150 sq ft/gal (very porous surface) Always use the number on the actual tin label — not a generic estimate. Different paints from the same brand can have very different coverage rates.

What is the difference between coverage and hiding power?

These are two different properties: • Coverage (spreading rate): How far the paint spreads in area per litre. A high-coverage paint goes far. • Hiding power (opacity): How well the paint covers the previous colour underneath. A high-hiding-power paint requires fewer coats to achieve a solid finish. A paint can have high coverage but low hiding power — it spreads far but shows the old colour through. This is common with cheap paints and very light/pastel shades. For dramatic colour changes (e.g. dark red to white), use a paint with high hiding power even if the coverage rate (m²/L) is slightly lower. You'll use fewer coats overall.

How do I convert m²/litre to sq ft/gallon?

Conversion formula: Sq ft/gallon = m²/L × 3.785 / 0.0929 = m²/L × 40.74 Common conversions: • 10 m²/L = 407 sq ft/gal • 12 m²/L = 489 sq ft/gal • 14 m²/L = 570 sq ft/gal • 400 sq ft/gal = 9.82 m²/L • 350 sq ft/gal = 8.59 m²/L • 300 sq ft/gal = 7.36 m²/L The reverse: m²/L = sq ft/gal × 0.0929 / 3.785 = sq ft/gal / 40.74

Why does porous or rough surface need more paint?

A porous surface (bare plaster, brick, raw wood, masonry) absorbs paint into its structure rather than forming a film on top. This means the actual coverage achieved can be 30–60% less than the tin states. Surface types and their impact: • Smooth emulsion (existing paint): 100% — full coverage as stated • Lightly textured surface: ~85% of stated coverage • Heavy artex or rough texture: ~70% of stated coverage • New plaster (must be mist-coated first): 50–60% — severely reduced • Bare brick: 30–50% of stated coverage • Smooth concrete (sealed): 80% of stated coverage For new plaster: always apply a mist coat (emulsion diluted 1:5 with water) as a sealing primer before painting. This dramatically improves coverage of subsequent coats and prevents the patchy 'flash' appearance.

Can I use this calculator for exterior paint?

Yes — the same formulas apply. However, exterior paint coverage rates differ from interior paint: • Exterior masonry paint: 4–6 m²/L (5–8 sq ft/gal equivalent) — porous surface absorbs heavily • Exterior gloss (wood trim): 12–14 m²/L • Exterior primer: 8–10 m²/L • Weathershield / all-weather paint: 8–12 m²/L depending on formulation For exterior masonry, enter a coverage rate of 5–6 m²/L in the calculator to get an accurate quantity. The default of 12 m²/L is for smooth interior walls — using it for exterior masonry will significantly under-estimate the paint needed.

Paint Coverage Calculator — Litres, Area & Coverage Rate

The Paint Coverage Calculator works in three bidirectional modes. 'Litres to Area' tells you how much surface a tin of paint will cover. 'Area to Litres' tells you how much paint you need for a given area. 'Coverage Rate' tells you what spreading rate is needed to cover a given area with what you have — and whether tha..

HOW MUCH AREA CAN I PAINT?

Enter how much paint you have and its coverage rate — find out what area it will cover.

PAINT QUANTITY

COVERAGE RATE (from tin label)

m²/L

Common: walls 12, ceiling 10, primer 8, masonry 5

NUMBER OF COATS

AREA YOU CAN PAINT

30.00 m²

= 323 sq ft

2 coats of 5.00 L at 12.0 m²/L

COVERAGE GAUGE

CALCULATION SUMMARY

Coverage rate12.00 m²/L (489 sq ft/gal)

Paint available5.00 L (1.321 gal)

Coats2 coats

Area coverable30.00 m² (323 sq ft)

COVERAGE RATE REFERENCE

Paint typem²/Lsq ft/gal

Masonry paint4–6163–244

Primer / undercoat8–10326–407

Standard emulsion10–12407–489

Ceiling paint10–11407–448

Eggshell / satinwood12–14489–570

Gloss (wood & metal)12–14489–570

US standard (all-in-one)~10~400

UNIT CONVERSIONS

1 L0.264 US gallons

1 US gallon3.785 litres

1 m²10.76 sq ft

10 m²/L407 sq ft/gal

12 m²/L489 sq ft/gal

400 sq ft/gal9.82 m²/L

Created with❤️byeaglecalculator.com

HOW TO USE

1
Choose your calculation mode. 'Litres to Area' answers 'how much can I paint with this tin?' — enter your paint quantity and the coverage rate from the label. 'Area to Litres' answers 'how much paint do I need?' — enter your area and the coverage rate. 'Coverage Rate' answers 'will this paint cover this area?' — enter both the litres you have and the area to cover.
2
Enter your known values. Switch between litres and gallons for paint quantity, and between m² and sq ft for area. Use the preset buttons for common tin sizes (1L, 2.5L, 5L, 10L) or common areas. Enter the coverage rate from your paint tin label — it is always printed as 'X m² per litre' or 'X sq ft per gallon'.
3
Set the number of coats. The same tin of paint covers twice as much in 1 coat as in 2 coats. If you plan 2 coats, the calculator halves the effective coverage. This is the most commonly missed step when estimating paint quantities.
4
Read your result — and check the coverage gauge on the right. The coloured gauge shows where your coverage rate falls: low (masonry/primer range), standard (typical emulsion), or high (gloss/premium topcoat). In 'Coverage Rate' mode, a quality assessment tells you whether the required rate is achievable with standard paint.
5
Use the coverage reference table on the right to look up typical rates for different paint types, and the unit conversion table to quickly switch between metric and US imperial values without re-calculating.

WORKED EXAMPLE

Three worked examples: MODE 1: Litres to Area I have a 5L tin of emulsion (coverage 12 m²/L). How much wall can I paint in 2 coats? Area = Litres × coverage / coats = 5 × 12 / 2 = 30 m² In sq ft: 30 / 0.0929 = 323 sq ft MODE 2: Area to Litres My bedroom walls are 38.95 m². How many litres of primer (8 m²/L) do I need for 1 coat? Litres = Area × coats / coverage = 38.95 × 1 / 8 = 4.87 L Buy: 1 × 5L tin (will have some left over for touch-ups) MODE 3: Coverage Rate I have 2L of paint and need to cover 20 m² in 1 coat. What coverage rate do I need? Coverage = Area × coats / litres = 20 × 1 / 2 = 10 m²/L In US: 10 × 3.785 / 0.0929 = 407 sq ft/gal Assessment: 10 m²/L is achievable — standard emulsion runs 10–12 m²/L. But it will be a thin coat — on a porous surface you may need 2 coats.

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Last updated: April 29, 2026 · Formula verified by EagleCalculator team · Eagle-eyed accuracy for every calculation.