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Paint Cost Calculator

Work out what painting a room will cost — paint and primer quantities at the prices you enter, from the room size or an area you already know.

Paint quotes are hard to compare because nobody states the same thing. This calculator states everything: the area, the coats, the coverage, the prices — and the total for paint and primer together.

All prices are yours to enter. The site publishes no prices and guesses none.

If you know the area, enter it and leave the room fields alone. Otherwise leave this blank and enter the room below.
Each door deducts 21 ft² (1.95 m²). Only used when the area is blank.
Each window deducts 15 ft² (1.39 m²). Only used when the area is blank.
Usually 2 coats.
Enter your local price — the calculator never guesses prices.
Enter 0 if no primer is needed.
Only used when primer coats are above 0.
Only used when primer coats are above 0.

Formula

paint needed = area × paint coats ÷ paint coverage paint cost = paint needed × price per gallon primer needed = area × primer coats ÷ primer coverage primer cost = primer needed × primer price total cost = paint cost + primer cost

All lengths are converted to a single unit before the calculation: 1 ft = 0.3048 m, 1 in = 25.4 mm, 1 ft² = 0.09290304 m², 1 yd² = 9 ft². Material quantities are rounded up — you cannot buy part of a tile, plank or bag.

How to use this calculator

  1. Enter the area if you know it, or the room size with doors and windows.
  2. Enter paint coats, coverage and price.
  3. Add primer coats, coverage and price if primer is needed (0 to skip).
  4. Read the paint cost, primer cost and total.

Worked example

Area381 ft² (12 × 15 ft room, openings deducted)
Paint (2 coats, 350 ft²/gal, $45/gal)381 × 2 ÷ 350 = 2.18 gal → 2.18 × $45 = $98.10
Primer (1 coat, 300 ft²/gal, $30/gal)381 × 1 ÷ 300 = 1.27 gal → 1.27 × $30 = $38.10
Total$98.10 + $38.10 = $136.20

Check it by hand: every step above uses the formula in the box. If your numbers match the example inputs but the calculator gives a different answer, please report it via the contact page.

Frequently asked questions

What does the paint cost calculator include?

Paint and primer, at the prices you enter, for the area and coats you specify. It does not include brushes, rollers, tape, dust sheets or labour — add those separately.

Why is the cost based on exact gallons, not whole gallons?

Because the cost of the paint you use is the exact quantity times the price. The whole gallons to buy are shown on the paint calculator — the difference is the leftover paint you keep for touch-ups.

How do I estimate labour cost?

Painters usually quote by the room or by the day, not by the gallon. Get two or three local quotes for labour and add them to the material cost here.

Can I use this for an exterior paint job?

Yes — the maths is the same. Enter the exterior wall area (or the room-style measurement of the elevation) and the exterior paint's coverage and price.

Related calculators

Estimates only. Results are for planning. Measure twice, confirm box coverage and tile sizes on the packaging you buy, and follow the manufacturer's instructions. See the disclaimer.