How Much Extra Paint Does a Spray Gun Use?

A paint sprayer can save you an enormous amount of time when you’ve got something that needs a fresh coat of paint.  But…how much spray paint do I need?

how much spray paint do i need
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How Much Extra Paint Does a Spray Gun Use?

When using a spray gun for paint, you’ll need to have some extra paint on hand to get the job done.

And it really depends on the type of spray gun that you’re planning to use.

Before you get started, it’s important to make sure you cover everything in your home.  This includes taping off your windows, and remove anything that you don’t want to get ruined.

Even with your best efforts to reduce paint splatter, a spray gun will always leave atomized paint in the air.

Paint Sprayers Vs Roller

Using a paint sprayer, no matter which type you decide to purchase, will always use more paint than a roller.  This is because of atomization.  When the paint is mixed with air inside the gun, it’s shot out of the nozzle is tiny drops. 

Some of those drops won’t make it onto the surface you’re painting.  This is why you mask off all of the things in your area that you want to keep paint free.  That is called paint waste. 

It’s the price you pay for a smooth, professional looking paint job in less time than with a brush or roller.

How Much Spray Paint Do I Need?

It depends on what type of spray gun you have chosen for your job.  This changes the amount of paint you will need to budget for your job.  Does a paint sprayer use more paint than a roller?  You bet it does.  Even with the best paint sprayer, you will use more paint than if you painted with a roller.

So, how much spray paint do you need? What is paint coverage spray vs a roller?  Brushes/rollers 1 can, HVLP sprayers 1.2 cans, Airless sprayers 1.4 cans, and poor spraying technique, 1.5 extra cans.

Application MethodPaint Use Ratio
Brush/Roller1 Can
HVLP Sprayer20% More
Airless Sprayer40% More
Sprayer (Poor Spraying Technique)Up to 50% More

With An HVLP spray gun, you should plan to have about 20% more paint on-hand than you think you’ll need. This paint budget will make sure you have enough to get your spray painting done.

Most folks use their HVLP spray guns outside for painting exteriors or fencing. 

A standard ratio for using this an interior paint sprayer vs a roller, is about 1.5 cans of paint to 1 can of paint.  But depending on how much PSI you use, your ratio could be 2:1 or even 3:1 on a windy day outside.

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With an airless paint sprayer,  you will use 40% more paint than if you brushed or rolled.  That means 40% of the paint that you’re spraying ends up somewhere else besides your paint surface.

Poor spray painting techniques can increase this ratio to 50/50.

Is it better to roll or spray paint?

Spraying paint results in more even, smooth finish that dries faster. Rolling is cheaper and uses less paint, but can leave runs, uneven paint and takes much longer to dry.

Does a paint sprayer use more paint than a brush?

Yes, because paint sprayers mix air and paint together (atomization), some of the paint ends up floating in the air and landing on random surfaces. With a brush, all the paint ends up on your surface.

How many square feet does a gallon of paint cover when using a sprayer?

Depending on the type of paint sprayer, and your skill level, you will end up covering less square feet per gallon, so it’s hard to say. An airless sprayer has more overspray, where an HVLP paint sprayer has less overspray and will cover more square feet per gallon than an airless. Typically, you should be able to cover about 35-40 square feet per gallon.

How much Spray Paint does an HVLP Spray Gun Use

High Volume Low Pressure (HVLP) spray guns are fairly comparable to brushes and rollers in the amount of paint that they use.

This is because the flow result is very predictable and you’re usually within 10-12 inches of the surface being painted.  Painting closer to the surface reduces the amount of paint pollution that you put into the air.

With this type of spray gun, you should plan to have about 20% more paint on-hand than you think you’ll need.

High Pressure Spray Guns Work Best Outdoors 

Using a high pressure spray gun with an air compressor atomizes a lot of paint into the air.

You can avoid some paint waste by using a gravity-style paint gun, which accepts the high pressure rate.  But this is an added cost to your tool investment.

This type of spray gun tends to have a premium price point and can cost up to 4x more than your basic paint sprayer.

Airless Paint Sprayers: How Much Spray Paint do They Use

Airless paint sprayers are great for work that needs to take place above your head – such as with a ceiling.

With this type of sprayer, up to 40% of the paint that you’re spraying from the gun is going to end up somewhere else besides the surface you’re painting.

You will also need to make sure your spray gun tips are in good working order. You can multiply your paint use by 2-3x just because you’ve got a blow tip or one that has been overused.

Remember that backrolling may also be necessary to even out the coat of paint that has been sprayed onto the surface.

Keep these tips and ratios in mind before you get started and you’ll be able to save time on your project even if you are using a little extra paint.