How much paint do I need?

How to calculate how much paint you need

To calculate how much paint you need, start by measuring the width of each wall and the height of the room from floor to ceiling. Include the ceiling dimensions if you plan to paint it as well. 

Find the square footage of triangular or sloping walls — like in rooms with vaulted ceilings — by multiplying the length of the base of the triangle by the height at the highest point and dividing by two.

To ensure you have enough paint, do not subtract any square footage for windows and doors unless they significantly reduce the square footage of the wall.

How many square feet does a gallon of paint cover?

Typically, a gallon of paint covers anywhere from 350 to 400 square feet, making it sufficient to cover a small space, such as a bathroom. Depending on the number of coats you intend to paint, one or two gallons of paint is the average amount for a standard room. To be most precise, consult the manufacturer's advice on the label. 

How much primer do you need?

Primer is essential when painting a room. Like paint, a gallon can cover 350 to 400 square feet. You can use the same result from the calculator to determine how many gallons you need per coat of primer. However, the number of coats you apply will depend on a few factors.

• Drywall and unfinished walls may require two coats of primer to help the paint absorb more evenly.
• Painting over dark or bright colors may also require two or even three coats of primer. To cancel out the previous color, you may need to request a tinted primer from your paint store.
• Neutral colors may only need one coat of primer to prep the wall for your new color choice.

How can I pay for my painting project?

According to Angi, the average cost for a gallon of paint ranges between $20 and $70. However, additional costs may include primer, brushes, rollers, paint trays, painter's tape and drop cloths. Depending on the amount of paint required and any extra supplies needed, a painting project can cost hundreds of dollars. If you need to finance your project, consider these options: