How to measure a ceiling for paint
Last reviewed: November 2, 2026
Multiply the room's length by its width. Height doesn't matter for a flat ceiling. If the room isn't a simple rectangle, split it into rectangles and add them up.
Many paint calculators leave ceilings out. Benjamin Moore’s, for example, says its results don’t include the ceiling, so it’s worth working this out separately.
A rectangular ceiling
Measure the room at floor level, which is easier and safer than reaching up. In a room with straight walls, the floor and ceiling have the same dimensions.
- 14 ft × 12 ft = 168 sq ft
- 4.2 m × 3.6 m = 15.12 m²
An L-shaped ceiling
Split the L into two rectangles, work out each, and add them.
In this example, 160 + 36 = 196 sq ft.
The calculator takes one length and one width, so enter the total area another way: use a length of 196 ft and a width of 1 ft. The area will be correct, and only the area affects the paint result.
From area to paint
Paint = area × coats ÷ coverage per coat.
| Input | US example | Metric example |
|---|---|---|
| Area | 168 sq ft | 15.12 m² |
| Coats | 2 | 2 |
| Example coverage per coat | 350 sq ft/US gal | 12 m²/L |
| Paint | 0.96 US gal | 2.52 L |
These coverage values are only examples. Use the figure for your product. If you’re using a different paint on the ceiling, it may have a different coverage, so keep it separate from your wall figure.
How many coats
This depends on the product and the job. Sherwin-Williams specifies two coats of SuperPaint on the surfaces its data sheet lists, while Benjamin Moore lists 1 or 2 coats for Regal Select Flat. Check the instructions for your paint.
Things this doesn’t cover
These figures are for flat ceilings. Sloped, vaulted, and coved ceilings aren’t handled by the calculator. If you can’t reach a ceiling safely from a stable platform, get help.