Paint Calculator
🇨🇦 Canada version
Canadian rooms are often described in feet while paint is sold by the litre, which makes the label hard to use. This version opens in feet and litres, converts the typical 12 square metres per litre into square feet per litre, and rounds each product up to whole 2.5 litre cans.
Use Paint Calculator online
Paint Calculator
Work out how much paint a job really needs — walls, ceilings and trim, adjusted for texture, colour change and the number of coats — then turn it into a shopping list.
Area to cover, by room
Canada rules and figures
- Canadians usually give room sizes in feet, while paint is sold by the litre, so this page pairs square feet with litres.
- Coverage of 12 m² per litre, about 129 square feet, is a typical figure from manufacturers and not an official value, so compare it with your can.
- Federal GST of 5% applies on top of the shelf price of paint, and some provinces add HST or sales tax, so check whether your price includes tax.
- Cans start at 2.5 litres and the price stays empty until you fill it in.
Sources: Canada Revenue Agency: Canada tax authority (GST/HST) (checked 2026-11-08)
How the Paint Calculator works
Room sizes stay in feet, and the spread rate is shown in square feet per litre. Perimeter, height and standard door and window sizes give the wall area, and coats and the spread rate give litres.
litres = (sq ft × coats) ÷ (sq ft per litre ÷ texture ÷ colour); cans = litres ÷ can size, rounded up
- The starting spread rate of 12 m² per litre is shown as 129 sq ft per litre for wall and ceiling paint and 111 for trim and primer, since the fields hold whole numbers above 50.
- Doors deduct 2.67 × 6.67 ft and windows 3 × 4 ft. Skirting is taken as 6 in high and casings as about 3.5 in wide.
- The colour slider defaults to 50 and adds 17.5% to wall and trim paint. Texture multiplies use by up to 1.6 for brick or stucco.
- Choose Units for feet and US gallons or metres and litres. The can starts at 2.5 litres and no price is filled in.
How to use the Paint Calculator
- Enter the rooms in feet. Type each room’s length, width and ceiling height in feet and count the doors and windows.
- Choose units if needed. Feet with litres is the Canadian default. Open Units to use US gallons or metres.
- Pick the surfaces. Tick walls, ceiling and trim per room. Basement walls often need only the first.
- Set the job type. On Paint needed pick the surface, such as new drywall or textured stucco, then set the colour change and primer.
- Add a price and copy. Enter the can price in dollars, then copy the list or export the sheet.
Example: The two starter rooms in feet, 2.5 litre cans
The 18 × 14 × 9 ft living room and the 12 × 11 × 9 ft bedroom give 900.57 sq ft of net wall, 252 sq ft of ceiling and 129.93 sq ft of trim. Wall paint at 129 sq ft per litre, cut to 109.79 by the colour slider, needs 16.41 litres for two coats (7 cans). The ceiling needs 3.91 litres (2 cans) and the trim 2.75 litres (2 cans), so 23.06 litres and 11 cans in all.
When to use the Paint Calculator
- Finishing a basement. Add the basement rooms, tick walls and ceiling, and choose new drywall with primer before buying.
- Repainting a condo. Enter each room in feet and see litres per product, then match them to the cans on the shelf.
- Stucco or brick exterior walls. Select the brick or stucco texture to see how much extra paint the rough surface uses.
- US versus Canadian cans. Switch between litres and gallons to compare the label of a US paint with a Canadian one.
What the Paint Calculator does not do
- The starting spread rates are typical manufacturer figures, not an official standard, so a tin that states a different rate needs that figure typed into the spread-rate box. Other countries start with litres and no price, which you enter.
- Doors and windows use one standard size each, so a patio door or a large picture window is under- or over-deducted.
- Rooms are rectangles with flat ceilings and no alcoves, stairs, gables or radiators.
- The texture and colour factors are rules of thumb, not a paint maker's data. Check the spread rate printed on your tin.
- Nothing is saved: the rooms reset to the two examples when you reload.
When something else is a better fit
- When you want floor area, perimeter and a boxes-of-material order for flooring, use the Room Measurement Calculator.
- When you need to convert gallons, litres or square measures, use the Unit Converter.
- When the surface is exterior brick, a ceiling with beams or a spray job, use the paint manufacturer's own calculator or a trade quote.
Questions about the Paint Calculator
How many litres of paint for an 18 by 14 foot room?
With a 9 ft ceiling, 2 doors and 2 windows, the walls need about 9.41 litres for two coats at the default settings. The full starter job, with bedroom and ceiling, is 23.06 litres.
Why does it show 129 sq ft per litre?
The typical 12 m² per litre is converted to square feet, which is 129 when rounded for the box. Type the figure from your can if it is different and the totals follow it.
Can I work in metres instead?
Yes. Open Units and pick metres and litres, and the room sizes you typed convert. Canada officially uses metric, but many homeowners still measure rooms in feet.
How much does a dark colour add?
The slider at 50 adds 17.5% to wall and trim paint, and at 100 it adds 35%. Primer covers wall, ceiling and trim area once and is off until switched on.
Does the price include tax?
It uses whatever you type. Federal GST is 5% and some provinces add provincial tax, so enter the total you would pay at the till if you want the cost to match.