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Paint Calculator

How much paint you need — by room size, coats, and coverage.

Buying too little paint means a second trip to the store mid-job (and hoping the same batch matches). Buying too much wastes money. This calculator accounts for your wall area, doors, windows, and number of coats to get you the right amount with a sensible buffer.

Paint needed (2 coats)
6.04 L
Wall area (net)
30.20 m²
Total painted area
60.40 m²
Round up to buy
7 L

Coverage estimate: ~10 m² per liter (or ~350 ft² per US gallon). Porous walls and dark-to-light repaints use more. Buy ~10% extra for touch-ups.

How Paint Coverage Is Calculated

Paint manufacturers quote a theoretical coverage rate — typically 10–12 m² per litre. Real-world coverage is always lower because of surface texture, porous walls, roller vs brush application, and paint consistency.

  • Smooth drywall (primed): ~10 m²/L
  • Unpainted new drywall: 7–8 m²/L (very porous)
  • Textured walls: 7–9 m²/L
  • Rough masonry or brick: 4–6 m²/L
  • Ceiling paint often covers slightly more due to flatter surface and less doorframe cutting

Paint Finishes: Choosing the Right Sheen

The sheen level affects both appearance and durability. Higher sheen = more washable and moisture-resistant but shows imperfections more. Lower sheen = hides imperfections but harder to clean.

  • Flat/matte: hides surface flaws, best for ceilings and low-traffic bedrooms, not cleanable
  • Eggshell: slight sheen, good for living rooms and bedrooms, wipeable
  • Satin: medium sheen, best for hallways and family rooms that see traffic
  • Semi-gloss: reflective, water-resistant, ideal for kitchens, bathrooms, and trim
  • Gloss: most durable and reflective, best for doors, cabinets, and furniture — shows every imperfection

Pro Tips to Minimise Paint and Maximise Finish Quality

The paint itself is rarely the problem — preparation and application make the difference between a professional and an amateur result.

  • Sand glossy surfaces lightly before repainting — paint adheres better to a dulled surface
  • Fill holes and cracks with filler, sand smooth, and spot-prime before applying finish coats
  • Always 'cut in' the edges with a brush before rolling — rolling first leaves dried lines
  • Don't overload the roller — thin coats dry faster and look better than thick ones
  • Buy 10% more than calculated: touch-ups over time are much easier with the same batch

How to Calculate How Much Paint You Need

Four steps to calculate the right amount of paint for a room.

  1. 1
    Measure the room
    Measure length, width, and ceiling height. You don't need to measure every wall separately — the calculator uses the perimeter × height formula.
  2. 2
    Count doors and windows
    Enter the number of standard doors (deducted at ~1.8 m² / 20 ft² each) and windows (~1.5 m² / 16 ft² each). These are approximate but realistic for most residential spaces.
  3. 3
    Set the number of coats
    Almost always 2. Use 3 for severe colour changes or dark-to-light transitions. Use 1 only for touch-up work on the same colour over a primed surface.
  4. 4
    Add 10% and round up
    The calculator shows the exact amount needed. Add 10% and round up to the nearest litre or gallon for the final purchase quantity.

FAQ

How much area does 1 liter of paint cover?
Roughly 10 m² per coat on smooth, primed drywall. Textured or porous walls may need 7-8 m²/L. Premium paints often claim more but perform similar in practice.
Do I need 1 or 2 coats?
Almost always 2. A single coat on colored or porous walls looks patchy. Skip the second only when repainting the same light color on well-primed walls.
Should I prime first?
Yes when changing from dark to light, covering stains, or painting new drywall. A single coat of primer is cheaper than 3 coats of finish paint.
What finish (matte, satin, gloss) should I use?
Bedrooms and living rooms: eggshell or satin — easier to clean than flat, less reflective than semi-gloss. Kitchens and bathrooms: semi-gloss or gloss — moisture and grease resistant. Trim, doors, and cabinets: semi-gloss or gloss for durability.

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