Ceiling Paint Calculator
Estimate paint needed to cover a ceiling.
Last updated 2026-08-21
What Is a Ceiling Paint Calculator?
The ceiling paint calculator estimates the gallons needed to cover a ceiling in one or more coats. You enter the ceiling length and width and the number of coats, and it returns the paint quantity using the standard 350 sq ft per gallon rate. It removes the guesswork from a task many homeowners put off because they cannot judge how much paint a ceiling drinks.
How It Works
Gallons = ceil((Length × Width × Coats) ÷ 350).
Example
A 20 ft × 15 ft ceiling with 2 coats: (300 × 2) ÷ 350 = 2 gallons.
How to Calculate
- Measure the ceiling length and width. A 20 ft by 15 ft ceiling has an area of 20 × 15 = 300 sq ft.
- Enter both dimensions into the calculator.
- Choose the Number of Coats. Two coats are typical for a fresh ceiling. For 2 coats you need 600 sq ft of coverage.
- Divide total coverage by the coverage rate: 600 ÷ 350 = 1.71 gallons.
- Round up to 2 gallons. Ceiling paint is usually flat, which can be slightly thirstier on fresh drywall, so buying one extra gallon is a safe move.
Gallons to paint a ceiling (2 coats)
| Ceiling size | Area | Gallons (2 coats) |
|---|---|---|
| 10 × 10 ft | 100 sq ft | 1 |
| 12 × 14 ft | 168 sq ft | 1 |
| 15 × 15 ft | 225 sq ft | 2 |
| 20 × 15 ft | 300 sq ft | 2 |
| 20 × 25 ft | 500 sq ft | 3 |
Sources
Frequently Asked Questions
Do ceilings need the same paint as walls?
Flat ceiling paint is common because it hides imperfections, but flat wall paint also works.
Is coverage the same as walls?
Yes, roughly 350 sq ft per gallon per coat for smooth ceilings.
Should I prime first?
Primer is recommended on bare or stained drywall; account for it as an extra coat.
Estimate the cost with the Paint Cost Calculator or browse Paint Calculators