How Much Paint Do You Need for a Room? Formula and 12 x 12 Example
Quick answer: A 12 x 12 ft room with 8 ft walls, one door, and one window needs about 2.1 gallons of paint for two coats. That assumes 350 sq ft of coverage per gallon and a 5% waste allowance. In practice, buy two gallons plus a quart, or three gallons if you want a full spare can.
Nobody wants to stop mid-wall for another can, and nobody wants a garage full of leftovers. The way to avoid both is a short calculation. The free
The Formula
1. Gross wall area = 2 x (length + width) x wall height
2. Paintable area = gross area minus doors and windows
3. Paint needed = paintable area x coats / coverage per gallon, plus a waste allowance
Standard deductions are 21 sq ft for each door (3 x 7 ft) and 15 sq ft for each window (3 x 5 ft).
Worked Example: 12 x 12 ft Room
• Gross area: 2 x (12 + 12) x 8 = 384 sq ft
• Deduct one door and one window: 384 - 21 - 15 = 348 sq ft
• Two coats: 696 sq ft of coverage
• At 350 sq ft per gallon: 1.99 gallons
• Plus 5% waste: about 2.09 gallons
The
Coverage per Gallon
Interior wall paints typically list 350 to 400 sq ft per gallon on smooth, primed surfaces. Starting at 350 is conservative, which protects you from running short. Use a lower number for rough or porous surfaces, new drywall, and big color changes, and always check the label of the product you are buying.
Surface | Planning note
Smooth, previously painted wall | Start at 350 sq ft per gallon
Rough texture or porous surface | Use a lower coverage figure
New drywall | Prime first, then paint
Dark to light color change | Prime or plan extra coats
What the Calculation Does Not Include
The wall formula does not include the ceiling, trim, or baseboards. Ceilings are usually estimated separately. Add extra for trim if you are painting it the same color.
Buying Tips
• When you need four gallons or more, a 5-gallon bucket is usually cheaper.
• Buy all the paint for a room together, or mix cans together, so the color matches.
• Keep leftovers for touch-ups and label the lid with the color name and number.
Basements, Garages and Concrete
Painting a basement or garage room often goes hand in hand with repairing a concrete floor. If you are patching or pouring a small slab, use the
Frequently Asked Questions
How much paint do I need for a 12 x 12 ft room?
About 2.1 gallons for two coats with one door and one window, at 350 sq ft per gallon and 5% waste.
How much does a gallon of paint cover?
Interior wall paint typically covers 350 to 400 sq ft per gallon on smooth, primed surfaces. Check the label.
Is the ceiling included in the estimate?
No. The wall formula covers walls only, so estimate the ceiling separately.
Ready to Buy?
Measure the room, count the doors and windows, run the numbers, and round up to a practical can size. Confirm the coverage on the label, buy from a single batch, and keep a small amount for touch-ups. These figures are estimates and depend on your surface and technique.
Quick answer: A 12 x 12 ft room with 8 ft walls, one door, and one window needs about 2.1 gallons of paint for two coats. That assumes 350 sq ft of coverage per gallon and a 5% waste allowance. In practice, buy two gallons plus a quart, or three gallons if you want a full spare can.
Nobody wants to stop mid-wall for another can, and nobody wants a garage full of leftovers. The way to avoid both is a short calculation. The free
Ziyaretçiler için gizlenmiş link,görmek için
Giriş yap veya üye ol.
at RenoCalcs include a paint tool that does it for you, and this guide shows how it works.The Formula
1. Gross wall area = 2 x (length + width) x wall height
2. Paintable area = gross area minus doors and windows
3. Paint needed = paintable area x coats / coverage per gallon, plus a waste allowance
Standard deductions are 21 sq ft for each door (3 x 7 ft) and 15 sq ft for each window (3 x 5 ft).
Worked Example: 12 x 12 ft Room
• Gross area: 2 x (12 + 12) x 8 = 384 sq ft
• Deduct one door and one window: 384 - 21 - 15 = 348 sq ft
• Two coats: 696 sq ft of coverage
• At 350 sq ft per gallon: 1.99 gallons
• Plus 5% waste: about 2.09 gallons
The
Ziyaretçiler için gizlenmiş link,görmek için
Giriş yap veya üye ol.
returns the paintable area, the gallons, and a suggested mix of cans, such as two gallons plus a quart.Coverage per Gallon
Interior wall paints typically list 350 to 400 sq ft per gallon on smooth, primed surfaces. Starting at 350 is conservative, which protects you from running short. Use a lower number for rough or porous surfaces, new drywall, and big color changes, and always check the label of the product you are buying.
Surface | Planning note
Smooth, previously painted wall | Start at 350 sq ft per gallon
Rough texture or porous surface | Use a lower coverage figure
New drywall | Prime first, then paint
Dark to light color change | Prime or plan extra coats
What the Calculation Does Not Include
The wall formula does not include the ceiling, trim, or baseboards. Ceilings are usually estimated separately. Add extra for trim if you are painting it the same color.
Buying Tips
• When you need four gallons or more, a 5-gallon bucket is usually cheaper.
• Buy all the paint for a room together, or mix cans together, so the color matches.
• Keep leftovers for touch-ups and label the lid with the color name and number.
Basements, Garages and Concrete
Painting a basement or garage room often goes hand in hand with repairing a concrete floor. If you are patching or pouring a small slab, use the
Ziyaretçiler için gizlenmiş link,görmek için
Giriş yap veya üye ol.
to estimate volume and bags while you plan your paint.Frequently Asked Questions
How much paint do I need for a 12 x 12 ft room?
About 2.1 gallons for two coats with one door and one window, at 350 sq ft per gallon and 5% waste.
How much does a gallon of paint cover?
Interior wall paint typically covers 350 to 400 sq ft per gallon on smooth, primed surfaces. Check the label.
Is the ceiling included in the estimate?
No. The wall formula covers walls only, so estimate the ceiling separately.
Ready to Buy?
Measure the room, count the doors and windows, run the numbers, and round up to a practical can size. Confirm the coverage on the label, buy from a single batch, and keep a small amount for touch-ups. These figures are estimates and depend on your surface and technique.