Paint Tips & Techniques: Estimating How Much Paint is Needed for a Room

Painting your home opens up a wonder of possibilities to express who you are and bring life to your space.  With the ability to add color, and even possibly be daring with the color that you choose, paint can bring life to your decorating vision.

After you’ve chosen your new hue, whether it be cranberry in the living room or caramel in the kitchen, you want to make sure you have all the supplies and tools before starting.  This is key to a successful paint job!  And to start off you need to know how much paint you’ll need, right?!  So….

How much paint will I need for my space?

To determine the amount of paint necessary for your space, here is the calculation:

Take the width of each wall, add them together, and multiply it by the height of the room.  Then divide that number by 400 and it will give you the number of gallons needed.

Example: My (fictitious) room is 10′ x 10′ x 8′ high.

1. Each wall is 10′ wide and I have 4 walls = The total overall width is 40′

2. Then multiply that by 8′ (the height of the room) = 320 square foot for the interior of the room.

3. 320′ square feet divided by 400 = 0.8 gallons

I would need 1 gallon for this room.

Remember, most applications (especially darker colors) require more than one coat. So for this (fictitious) room, I would want 2 gallons and you’d have about a half gallon leftover for touch-ups.

Are you saying to yourself, well my room has more than 4 walls and my ceiling height varies?  Can I still use this estimate?  YES!

My calculation is very general and most rooms are NOT a perfect square.  If your room has varying heights, a sloping ceiling, or a different configuration, use the same calculation but take the width x height for each individual wall first, then add them up.  Once you have that number, then divide by 400 to get your number of gallons needed.

Please note, the calculation is just an ESTIMATE…it’s not exact, but it’ll give you a good ballpark of how much paint you’ll need to avoid a trip back to the paint store OR too much paint leftover!

Some Painting Tips:

  • It’s always best to have left over paint than to use every last drop in the paint can.  It’s inevitable that you’ll have areas to touch-up with regular wear n’ tear and hand prints.  If you don’t have leftover paint, you could run the risk of the color not matching if you buy a new gallon at a later date.
  • If you live in an area where the temperature goes below freezing, store your paint(s) INDOORS.  I learned this the hard way ~ I had my paint in the garage and during the winter months went to use it.  NOPE…it was solid like a brick!

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