Glidden paints, loaded in
Glidden Diamond Interior Paint + Primer is the paint this paint calculator opens with, set to its data sheet’s figure of 400 sq ft for each gallon, while the product page offers it in three sizes: quart, gallon and 5-gallon pail. For the room already entered, two coats on the walls and the ceiling come to 2.49 gallons; the calculator buys that as 2 gallons plus 2 quarts.
One Coat Interior, Diamond Ceiling and One Coat Exterior are in the same Paint menu. They share the same coverage figure but not the same sizes: the ceiling paint comes by the gallon only, so a small ceiling rounds up to a whole gallon.
“Up to” 400 on a smooth surface
Glidden’s data sheets qualify the figure: 400 is the most a gallon covers, on primed, smooth, non-porous surfaces, and it leaves out paint lost to rough surfaces, porosity, application or mixing. New drywall, patched areas and stark color changes may need a primer or an extra coat. For those, type 300 or 350 into the coverage box, or turn on Primer first.
One coat, with conditions
The one-coat guarantee on Diamond and One Coat holds only for colors from Glidden’s designated one-coat collections. Any other color, and any uncoated surface, needs two, which is why Coats stays at 2 until you change it.
Glidden paints in the calculator: the range sold in the US
| Paint | For | Coverage, as stated | Tins |
|---|---|---|---|
| Diamond Interior Paint + Primer | Walls | up to 400 sq ft per gallon | 5 gal, 1 gal, 1 qt |
| One Coat Interior Paint + Primer | Walls | up to 400 sq ft per gallon | 1 gal, 1 qt |
| Diamond Ceiling Paint | Ceilings | up to 400 sq ft per gallon | 1 gal |
| One Coat Exterior Paint + Primer | Outside walls | up to 400 sq ft per gallon | 5 gal, 1 gal |
What one room takes in each
Two coats. Rooms: 12 × 12 ft room with 8 ft walls, one door, one window, walls and ceiling (ceiling only for a ceiling paint). Outside: 26 × 34 ft house with 17 ft walls and two gables.
| Paint | Area | Paint, 2 coats | Buy |
|---|---|---|---|
| Diamond Interior Paint + Primer (room, 400 sq ft/gal) | 498 sq ft | 2.49 gal | 2 × 1 gal + 2 × 1 qt (fewer cans: 3 × 1 gal) |
| One Coat Interior Paint + Primer (room, 400 sq ft/gal) | 498 sq ft | 2.49 gal | 2 × 1 gal + 2 × 1 qt (fewer cans: 3 × 1 gal) |
| Diamond Ceiling Paint (ceiling, 400 sq ft/gal) | 144 sq ft | 0.72 gal | 1 × 1 gal |
| One Coat Exterior Paint + Primer (house, 400 sq ft/gal) | 2,092 sq ft | 10.46 gal | 2 × 5 gal + 1 × 1 gal |
Coverage per coat for the Glidden range sold in the US, from the maker's pages linked above, checked September 2026. Glidden and its product names are its owner's trademarks, used only to describe the products; Meadow Tools is not affiliated with or endorsed by Glidden.