House paint prices: what does painting one room cost? Worked out line by line

How to work out the cost of paint: one formula

Pricing paint is like ordering khao man gai (chicken rice) for the whole office. You need to know how many people first, or you buy too little or end up throwing food away. For a wall, how many people means how many square metres.

The formula: measure the length around the room, multiply by the height and take off the doors and windows to get the wall area. Multiply that by the number of coats, then divide by the paint's coverage to get how much paint to buy. Then pick the tin size that gives you the best value.

• Wall area = room perimeter x height - doors and windows
• Area to paint = wall area x number of coats
• Paint needed = area to paint ÷ coverage

Worked example: a 3 x 4 metre bedroom in Voqe Wall Paint

A 3 x 4 metre bedroom, 2.6 metres high, has a perimeter of 14 metres. The wall area is 14 x 2.6 = 36.4 sq m. Take off about 4 sq m for one door and one window and you are left with about 32 sq m. Two coats make 64 sq m.

Voqe Wall Paint covers 35–40 sq m per gallon (3.785L) per coat. 64 ÷ 40 = 1.6 gallons and 64 ÷ 35 = 1.83 gallons, so you need about 1.6–1.8 gallons of paint.

Option one: buy two gallons at ฿1,299 each, which comes to ฿2,598. Option two: buy a 9L pail at ฿2,500, which gives you about 2.38 gallons of paint (9 ÷ 3.785) and covers 83–95 sq m per coat. It is ฿98 cheaper and leaves paint over for touch-ups or the ceiling, so the 9L pail is the better buy.

Price per litre: which size is the best value?

Voqe Wall Paint comes in 5 sizes. The 100ml sample bottle at ฿75 is for trying a colour. For the working sizes, broken down per litre: 0.946L at ฿399 is about ฿422 a litre, the 3.785L gallon at ฿1,299 about ฿343 a litre, the 9L pail at ฿2,500 about ฿278 a litre, and the 18L pail at ฿3,990 about ฿222 a litre.

If you are painting the whole house or several rooms in the same colour, an 18L pail gives you about 4.76 gallons (18 ÷ 3.785). It covers 166–190 sq m per coat, or about 83–95 sq m of wall in 2 coats, enough for roughly 2–3 bedrooms of 3 x 4 metres. You can double-check with the paint calculator on our website.

• 0.946L ฿399: a small wall or a single feature wall
• 3.785L ฿1,299: a ceiling or a small room
• 9L ฿2,500: one bedroom
• 18L ฿3,990: several rooms in the same colour

With primer and tools, what does the whole room cost?

For an old wall that has been painted before, use Voqe Primer old concrete, 3.785L at ฿630. For freshly rendered walls, use Voqe Primer new concrete, 3.785L at the same price, ฿630. Primer takes one coat; its coverage is listed on the product page. For tools, use a 9-inch roller and tray at ฿189 for the big walls and a 4-inch roller at ฿89 for the edges.

All in, for a 3 x 4 metre bedroom you paint yourself: 9L of paint ฿2,500 + primer ฿630 + 9-inch roller ฿189 + 4-inch roller ฿89 = ฿3,408. Divided by 32 sq m of wall, that is about ฿107 per square metre of wall. That doesn't include masking tape and dust sheets, which many households already have.

What a Mineral Finish feature wall costs, and whether to paint it yourself or hire an applicator

Voqe Mineral Finish covers 8–12 sq m per litre per coat, depending on the wall surface and technique. A headboard wall 3 metres wide and 2.6 metres high is 7.8 sq m. Two coats make 15.6 sq m, which takes 15.6 ÷ 12 = 1.3 litres to 15.6 ÷ 8 = 1.95 litres of paint. Set 2QT at ฿1,180 suits a wall this size. For a large wall or several walls, choose Set 2GL at ฿2,998.

If you want to seal the surface as well, Voqe Mineral Sealer, a clear satin, costs ฿1,400 for 0.946L and covers 145–155 sq m per gallon per coat. So 0.946L covers about 36–39 sq m (0.946 ÷ 3.785 = 0.25 gallons), more than enough for one wall.

Painting it yourself saves on labour and is fun. But if the house is large, you are short of time, or you want a mineral pattern from a steady hand, Voqe offers a Supply & Apply service with trained applicators. Labour depends on the size of the job and the condition of the walls. Ask us for a quote.