PaintCalc
Paint Calculator – Estimate Paint Quantity, Coverage & Cost Online
Our free paint calculator helps you figure out exactly how much paint you need for any project — from a single wall to a whole house. Whether you’re painting an interior room, an exterior facade, a ceiling, a fence, a deck, kitchen cabinets, doors, or trim, this online paint calculator gives you accurate results in litres, gallons, square feet, and square meters in seconds.
What Is a Paint Calculator?
A paint calculator is a simple tool that estimates the paint quantity required based on your surface area, number of coats, and the coverage rate of your chosen paint. Instead of guessing and either running short or overspending, you enter your room size, wall dimensions, and coat preferences, and the calculator tells you the exact paint amount needed — plus an approximate paint cost.
This paint estimate calculator works for interior paint jobs, exterior paint jobs, ceiling paint, wall paint, fence paint, roof paint, garage floors, cabinets, and even car and automotive paint projects.
How to Use the Paint Calculator
Using this paint calculator is easy:
- Enter your measurements — length, width, and height in feet or meters.
- Choose your surface type — walls, ceiling, exterior house, single wall, doors, trim, deck, or fence.
- Select the number of coats — most projects need 2 coats for full coverage.
- Set paint coverage — typically 350–400 sq ft per gallon or 10–12 m² per litre.
- Get instant results — paint quantity in litres or gallons, plus estimated cost.
You can calculate paint by room size, by square feet, by square meters, or per wall. It works whether you measure in feet, inches, meters, or m².
Paint Calculation Formula
The standard paint calculation formula is:
Paint Required = (Total Surface Area × Number of Coats) ÷ Coverage per Litre (or Gallon)
Subtract the area of doors and windows for accuracy. As a thumb rule, 1 litre of paint covers approximately 100–120 sq ft per coat on smooth interior walls, while textured or exterior surfaces absorb more.
Paint Coverage Guide
Understanding paint coverage per gallon helps you plan better:
- 1 gallon covers roughly 350–400 sq ft (1 coat)
- 2 gallons cover about 700–800 sq ft
- 10 gallons cover approximately 3,500–4,000 sq ft
- 1 litre covers around 10–12 m²
For a 1,000 square feet home interior with 2 coats, you’ll typically need 5–7 gallons or 20–25 litres of wall paint.
Interior Paint Calculator
Use the interior paint calculator for bedrooms, living rooms, kitchens, and bathrooms. It handles calculations for walls only, walls plus ceiling, or a full room including trim and doors. Perfect for interior room 2-coat projects, kitchen paint, and cabinet refinishing.
Exterior Paint Calculator
The exterior paint calculator estimates paint for your house siding, brick walls, stucco, or wood exteriors. Since exterior surfaces are more porous, add 10–15% extra to your total for absorption. Also useful for exterior house paint jobs, garages, and outdoor structures.
Ceiling, Fence, Deck & Trim Paint Calculator
Get precise quantities for:
- Ceiling paint — flat-finish coverage for standard 8–10 ft ceilings
- Fence paint — factoring in both sides and pickets
- Deck paint — including railings and steps
- Trim and doors — small surface calculations that need gloss or semi-gloss paint
Paint Cost & Estimate Calculator
Beyond quantity, our paint cost calculator gives you a price estimate based on your local paint rate per litre or per gallon. You can also factor in labour cost to build a full painting quote — helpful for both DIY homeowners and professional painters preparing quotations.
Whether you’re in the UK, US, Canada, Australia, NZ, South Africa, India, Pakistan, the Philippines, or Malaysia, the tool adapts to metric or imperial units and lets you enter local paint prices.
Compatible with Major Paint Brands
This paint calculator works with any brand, and coverage rates are aligned with popular manufacturer guidelines including:
- Dulux (Dulux Trade, Dulux Heritage)
- Asian Paints and Berger
- Sherwin-Williams and Benjamin Moore
- Behr, Valspar, Glidden, Kilz, and PPG
- Jotun, Nippon, Hempel, and Kansai
- Boysen, Davies, Rain or Shine (Philippines)
- Crown, Johnstone’s, Little Greene, Zinsser (UK)
- Resene, Taubmans, Wattyl, Haymes (AU/NZ)
- Plascon (South Africa) and Birla Opus, JSW, British Paints (India)
Simply plug in the coverage rate stated on your paint tin, and the calculator adjusts automatically.
Paint Quantity for Special Surfaces
The tool also supports:
- Structural steel — paint area calculation for beams and pipes
- Pipe painting — quantity per linear meter
- Automotive and car paint — volume needed for vehicles
- Spray paint usage — coverage per can
- Acrylic pour and paint pouring projects
Why Use an Online Paint Calculator?
- Save money — buy only what you need, avoid leftovers
- Save time — no manual calculations or guesswork
- Reduce waste — accurate estimates lower paint wastage
- Plan budgets — get instant cost estimates for quoting jobs
- Work in any unit — feet, inches, meters, m², litres, or gallons
Whether you’re a homeowner tackling a DIY project or a contractor preparing a painting quote, this paint calculator delivers reliable results every time.
Frequently Asked Questions
How much paint do I need for a room?
For an average 12×12 ft room with 8 ft walls (2 coats), you’ll need about 2 gallons or 8 litres of wall paint.
How much does 2 gallons of paint cover?
Two gallons cover approximately 700–800 square feet with a single coat.
How do I calculate paint for 1000 square feet?
For 1,000 sq ft with 2 coats, plan for 5–6 gallons or 20–24 litres.
Does the calculator include doors and windows?
Yes — subtract the area of doors and windows for a more accurate paint quantity.
Can I use it for commercial jobs?
Absolutely. The paint estimate calculator works for homes, offices, warehouses, and industrial coatings.
Try our free paint calculator now and get an accurate estimate of how much paint you need — plus the total cost before you start your next painting project.
