Paint Calculator: How Much Paint to Buy, Printable Chart
Standing in a room with a tape measure, you need a number you can take to the store. This calculator turns length, width, and ceiling height into a materials list with gallons and quarts, rounded up.
The coverage chart lists gallons for 1 and 2 coats across common wall areas. It uses the coverage field below. That field starts at 350 sq ft per gallon.
The worked example uses a 12 by 12 ft room with 8 ft ceilings. Use the controls below to enter your own dimensions.
Estimates only. Print at 100% with scaling off.
Coverage chart
| Surface | Room | Area | Coats | Coverage | Buy |
|---|---|---|---|---|---|
| Walls | Room 1 | 349 sq ft | 2 | 350 | 2 gallons |
Assumptions
- Surface type: Previously painted, smooth (×1)
- Wall/ceiling coverage: 350 sq ft/gal
- Primer coverage: 300 sq ft/gal
- Default door opening: 20 sq ft
- Default window opening: 15 sq ft
- Trim estimate width: 0.33 ft (rough)
Supplies checklist
- Painter's tape — 1 roll
- Drop cloths
- Roller covers — 2–3
- Angled brush
- Roller tray liners
- Spackle / filler
- Sandpaper
Estimates only. Check the coverage figure on your product before buying.
The Handy Pages · thehandypages.com
Room
Interior Paint Calculator
Interior rooms share the same math: perimeter times ceiling height, minus openings, times coats, divided by coverage.
Controls on this page let you add up to six rooms. Project totals sum areas first, then round up once.
Ceiling Paint Calculator
Ceiling area only: length times width. Example room is 12 by 14 ft.
Use controls on this page for your ceiling dimensions.
Exterior Paint Calculator
Exterior siding needs more product per square foot. Example uses lightly textured surface and primer.
Example footprint is 40 by 30 ft with 9 ft wall height.
Primer Calculator: How Much Primer to Buy
Primer has its own coverage figure. Example is 12 by 12 ft with bare drywall.
Toggle topcoat surfaces in the controls on this page if needed.
More paint presets
Handy gear for paint day
- Paint roller kit with tray for walls and ceilings (opens in new tab)
- Canvas or plastic drop cloths to protect floors and furniture (opens in new tab)
- Painter's tape for clean edges at trim and ceilings (opens in new tab)
- Coveralls or a paint-splatter work shirt you do not mind staining (opens in new tab)
As an Amazon Associate I earn from qualifying purchases. Full affiliate disclosure