How Much Paint Do I Need for My Project?

Paint with precision: Learn how to estimate the exact amount of paint needed for your project with this guide.

Whether you’re a professional painter or someone deciding to tackle that long-planned painting project in your own home, one of the most important things you need to figure out is how much paint is required for the task at hand. Buy too much and you’re stuck with extra paint you don’t need. And if you buy too little, you’ll find yourself running back to the hardware store when you could be finishing your paint job instead.

Once you’ve determined the paint color and finish (flat? satin? gloss?) and gathered your brushes, rollers, and drop cloths, it’s time to grab your tape measure and assess the size of the room or rooms you’re going to paint. Knowing the size of the room in square footage and some general guidelines regarding the coverage of a typical gallon will help you get a close approximation of the amount of paint needed.


Size Factors

A fresh coat of paint can go a long way toward freshening up a living space. If you are planning to spruce up an entire apartment, the overall size of your space is dictated by a number of factors. 

For example, the geographic region you live in makes a huge difference when it comes to the size of the average apartment. Not surprisingly, space is more of a premium in bigger cities than in smaller towns. For comparison, Seattle, Washington, has the smallest average size rental apartments in the country at 733 square feet, whereas Tallahassee, Florida, features the largest at 1,038 square feet. More square feet means more paint.

The number of bedrooms also impacts the overall size of a space. Here’s a guide to help give you an idea of the average square footage of the most common apartment options. 


Apartment Type Average Square Footage Number of Gallon Cans*
Studio 515 sq. ft. 2
1-bedroom 760 sq. ft. 2
2-bedroom 1,140 sq. ft. 3

* Note: Each gallon of paint can cover roughly 400 square feet.


If you’re painting a specific room only, here are the average sizes of the main types of rooms in a house or apartment. 

To check the square footage of a room yourself, simply measure each wall across from end to end. Then, measure from the floor to the ceiling. Standard ceiling height is under 10 feet so, using that math, you would need to measure each wall length times a height of ten feet to determine total square footage. 


See the examples below:

Room Type Size Number of Gallon Cans*
Bathroom (5x8) = 5x10 + 5x10 + 8x10 + 8x10 260 sq. ft. 1
Small Room (8x10) = 8x10 + 8x10 + 10x10 + 10x10 360 sq. ft. 1
Medium Room (14x14) = 14x10 + 14x10 + 14x10 + 14x10 560 sq. ft. 2
Large Room (18x18) = 18x10 + 18x10 + 18x10 + 18x10 720 sq. ft. 2

* Note: Each gallon of paint can cover roughly 400 square feet.


These examples reflect covering all four walls, but do not take into account windows or doors. Simply measure the dimensions of any windows or doors and subtract from the total. Also, some paint manufacturer sites feature handy online calculators to perform the math for you.


Don’t Forget the Ceilings! 

If you’re painting the ceilings, measure the dimensions of the room to determine the square footage. A small 8x10 room will have ceilings that cover 80 square feet. In many cases, the ceilings in an entire house or apartment are painted the same color (usually white) while the walls are painted different colors. If you’re going this route, add up the square footage of the ceilings in each room to find out how much paint is needed for the ceilings only.

In general, most professionals recommend painting the ceiling before the other walls in a room. That way, if you drip paint on one of the walls you can simply paint over it later.


Paint per Square Foot

The general rule of thumb is a single 1-gallon can of paint can safely cover up to 400 square feet with a single coat of paint. Per the chart above, that means a single gallon would easily be enough for an average small-sized room (360 square feet), while a larger room (720 square feet) will require 2 gallons. 

If you are planning a second coat, double the amount of paint to be sure you have enough. This is especially important if you are painting over a darker shade with a lighter color.

Also, some types of paints or certain textured walls need additional coverage, so be sure to ask an expert at the paint store or hardware store if you should account for these variables when determining the amount of paint for your job.


Other Considerations

Take into account the overall layouts and placement of fixtures and appliances in rooms such as bathrooms and kitchens. 

For example, while you may still want to paint behind a refrigerator, you can subtract the dimensions of built-in showers or tubs, as those areas of the room will not be painted. 

If you’re painting a larger room that calls for more than 1 gallon, combine 2 or more in a 5-gallon bucket to maintain color consistency.

All it takes is some pre-planning and a little basic math to make sure you have all the materials you need to get your paint job done quickly and efficiently. Remember, the quicker you complete your painting project, the sooner you can enjoy the look of that newly refurbished room.

Product Compliance and Suitability

The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.

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