Paint Calculator for Small Rooms and Apartments

This paint calculator for small rooms helps you work out exactly how much paint to buy, because one gallon covers about 350 square feet per coat, but the amount you actually need depends on your room size, ceiling height, doors, windows and how many coats you plan. Enter your room below and this free paint calculator works out exactly how many gallons or liters to buy, so you do not run short mid wall or waste money on extra cans.

How this paint calculator works

The calculator adds up your wall area from the room length, width and ceiling height, then takes off about 21 square feet for each door and 15 square feet for each window. It divides the paintable area by the standard coverage of 350 square feet per gallon (about 10 square meters per liter), multiplies by your coats, and can add 10 percent for waste and touch-ups. The result is always rounded up to whole gallons or liters, because paint is sold that way.

How much paint do I need? A paint calculator for small rooms, by room size

These worked examples use 8 foot ceilings, one door, two windows, two coats and the 10 percent waste allowance switched on.

Room size	Paintable area	Paint to buy
8 x 10 ft	237 sq ft	2 gallons
10 x 10 ft	269 sq ft	2 gallons
10 x 12 ft	301 sq ft	2 gallons
12 x 12 ft	333 sq ft	3 gallons
12 x 14 ft	365 sq ft	3 gallons
14 x 16 ft	429 sq ft	3 gallons

How much paint for a ceiling

Ceiling area is length times width. A 12 x 12 ft ceiling is 144 sq ft, so two coats is 288 sq ft, about 0.8 gallon at 350 sq ft per gallon. One gallon is enough for most small rooms.

Textured ceilings absorb more paint. Some guides suggest adding 20 to 30 percent. For color ideas, see our ceiling colors for small rooms.

How much paint for a small bedroom, bathroom, or studio apartment

For a small bedroom, use the 10 x 10 or 12 x 12 row in the table above. For color ideas, see our small room color guide.

For a small bathroom, about 1 gallon covers two coats on the walls. A 5 x 8 ft bathroom with one door and one window has about 173 sq ft of paintable wall. Do not count tiled areas or a tub surround you will not paint.

For a studio apartment, add up the wall area of each wall you will paint, subtract doors and windows, then divide by coverage. Painting only one or two walls or the main living area is often the practical choice.

How much paint for an accent wall

Multiply the wall width by the ceiling height, subtract any door or window, and divide by coverage. A 12 ft wide, 8 ft high accent wall with one window is 96 minus 15 = 81 sq ft per coat, so two coats is 162 sq ft, about half a gallon.

A quart covers roughly 100 sq ft, so two quarts will do it.

What changes how much paint you need

Rough or porous surfaces soak up more paint. Dark to light color changes may need an extra coat or a tinted primer. Fresh drywall or patched areas need primer first, and primer covers about 200 to 300 sq ft per gallon, less than paint.

The coverage printed on your can beats any general rule.

Tips for renters

Check your lease before you paint, and ask the landlord which color and sheen are on the walls. Some leases require repainting to the original color at move-out.

Keep a labeled can with the color name and sheen for touch-ups, and buy only what you need.

If painting is not allowed, see peel-and-stick versus paint.

Method and sources

Coverage and the door and window sizes used here are standard rules of thumb used by paint makers and DIY guides such as Bob Vila, This Old House, Angi, and The Old Farmer Almanac. They are estimates.

Always follow the coverage printed on your paint can. Last reviewed October 2026.

Tips before you buy

Dark colors going over light walls, and fresh drywall, can need a coat of primer or an extra coat, so plan for that before you start. Buy all your cans from the same batch number when you can, and keep a small labeled jar of the color for touch-ups. If you are painting cabinets rather than walls, our guide to painting kitchen cabinets for under $200 walks through the quantities for doors and frames. Choosing the color itself is easier with our paint colors for north-facing rooms and our best paint finish for small rooms guide.

Paint calculator questions