Ceiling Paint Calculator
Work out how much paint a ceiling needs — from the room size, the number of coats, and your ceiling paint's coverage.
Ceilings are the simplest paint job to estimate: one flat rectangle, no doors or windows to deduct. This calculator does that one job properly, with your paint's coverage and the coats you plan.
Use flat ceiling paint, work in sections, and keep a wet edge — the quantity is the easy part.
Your results
Enter your measurements and press Calculate.
Quantities are rounded up to whole tiles, planks, boxes or bags, after the wastage allowance. Cost appears only when you enter a price.
Formula
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
- Measure the room length and width.
- Enter the number of coats (usually 2).
- Enter the coverage from the tin.
- Add a price per gallon or litre if you want a cost estimate.
Worked example
| Room | 12 ft × 15 ft |
|---|---|
| Ceiling area | 12 × 15 = 180 ft² |
| Paint (2 coats, 350 ft²/gal) | 180 × 2 ÷ 350 = 1.03 gallons |
| To buy | ⌈1.03⌉ = 2 gallons |
| Cost at $35 per gallon | 1.03 × $35 = $36.05 (exact paint used) |
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 paint should I use on a ceiling?
Flat (matte) ceiling paint — it hides imperfections and does not reflect light. Do not use wall paint with a sheen on a ceiling unless you want every bump to show.
How many coats for a ceiling?
Two coats is standard. One coat can work if the ceiling is already white and in good condition, but a second coat evens out roller marks.
Do I deduct light fittings from ceiling paint?
No — the area is tiny, and you paint around fittings. The ceiling area is simply length × width.
Why is my ceiling paint estimate more than one gallon for a small room?
Because paint is sold in whole gallons: 1.03 gallons needed means 2 gallons to buy. The calculator shows the exact amount and the whole gallons separately so you can see both.
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.