Paint Calculator

How much does it cost to paint a room?

A DIY paint job typically costs $2–$6 per square foot of wall area including paint and supplies. Hiring a professional costs $3–$6 per square foot, which works out to roughly $300–$800 for a typical 12 × 12 ft room.

Cost to paint a whole house

• Interior (1,500 sq ft home): $1,500–$4,000
• Exterior (1,500 sq ft home): $1,800–$4,500
• Single accent wall: $100–$250

Factors that affect paint cost

• Paint quality: budget paint starts around $25 per gallon; premium brands run $50–$80 per gallon.
• Labor: professional painters charge $20–$50 per hour, plus setup.
• Prep work: patching, sanding, and priming add time and cost.
• Ceilings and trim: painting these in addition to walls increases the total.
• Color changes: going from dark to light often needs an extra coat or primer.

How much paint do I need?

One gallon covers roughly 350 square feet per coat (one litre covers about 10 m²). Wall area is the perimeter of all four walls times the room height, minus 20 sq ft (1.9 m²) per door and 15 sq ft (1.4 m²) per window.

• Most walls need two coats for even coverage.
• Rough or unpainted surfaces may require extra paint.
• Round up to the nearest whole unit — stores don't sell partial gallons or litres of tinted paint.

DIY vs. hiring a pro

Painting is one of the most DIY-friendly projects. If the walls are in good shape and you can reach them safely, doing it yourself usually saves 50% or more. Hire a pro for high ceilings, exteriors, or extensive prep.

Frequently asked questions

How many gallons of paint for a 12×12 room?

A 12 ft × 12 ft room with 8 ft walls has about 384 square feet of wall area. With two coats, you need about 2–3 gallons.

How much paint do I need for one wall?

Multiply the wall's width by its height, then divide by 350 square feet per gallon.

Do I need primer before painting?

Primer is recommended for bare drywall, stained surfaces, or big color changes. On clean, previously painted walls in a similar color, you can often skip it.