You are going to paint your outdoor walls. And in the middle of your work, you are out of exterior paint. And you don’t know what to do then.

You are probably thinking to use leftover interior paint on an exterior surface.

It seems like a brilliant idea. Using leftover interior paint can save money and time that you spend going to the store and buying. But you may also have some confusion:        

  1. Can I use interior paint outside?
  2. What happens if I use interior paint for the outside painting?

Answering these kinds of questions is not as easy as others think. And in this case, our article will help you.

We will talk about interior and exterior paint, the main differences between them, the outcomes of using interior paint, whether you can mix them together or not, and the best choice for exterior paint.

Can I Use Interior Paint Outside

What is Interior Paint?

Interior Paints are made for indoor usage. This paint doesn’t resist rain, snow, wind UV rays, and temperature changes.

Interior Paint resists every daily indoor event. You can clean it easily if it gets dirty. Besides, they have low volatile organic compounds (VOC).

This lessens health risks due to off-gassing. They produce less smell when you use interior paint indoors. You may also find no-VOC Interior Paint.

Compared to exterior paints it has less pigment and binding resins. It leads to easier cleaning.

Indoor Paints are mostly water-based than oil-based. Water-based Paints include latex and acrylic paints. Alkyd paints are considered oil-based paint.

Exterior Paint overview

Exterior Paint used to be oil-based in the past. Because oil-based paints were more durable. But modern science has changed the interior and exterior paint.

Now, most exterior paint is water-based with acrylic resins. Water-based latex paint is used on exterior surfaces.

Because it tends to be more durable than other types. Outdoor paints contain additives that give them longevity in the elements.

They have more specific additives to withstand outdoor events like weather-resistant chemicals and mildew.

So outdoor paint has to be capable of resisting snow, wind, rainfall, the sun rays, and both rising and falling temperatures.

Differences between Exterior and Interior Paint.

Paints are designed to be used outdoors or indoors. You can’t apply any paint on any kind of surface. Paints are designed to make a reliable surface in specific places.

Now, we will look through the main differences between exterior and interior paints.

Firstly, there are two main kinds of paint: water-based and oil-based. Yet, they are not designed for only interior use or exterior use. Both of them can be used on both surfaces. But you should consider some factors. 

For exterior surfaces, oil-based paints are better at resisting dirt. But you can use water-based latex paint on external surfaces because of its superior durability.

Exterior Paints have more additives to make the paint resist outdoor elements. They are more durable on outdoor surfaces.

Exterior paints have four basic compounds: pigments, solvents, additives, and resins. They also differ according to these components.


Pigment provides the paint with color. Interior paints have organic pigments for color. And specific types of organic pigments mostly fade when used as exterior paint. Exterior paints don’t contain these pigments.


          Binders are also additives. They are used to bind pigments together. And they provide adhesion to the painted surface. Binders of the exterior surface give the paint resistance to environmental hazards. 

Interior paints and exterior paints differ according to the type of liquids used.  Interior Paints are mostly water-based latex paints. They contain less amount of VOC (volatile organic compounds) than exterior paints.

What is VOC?

          Volatile Organic Compounds (VOCs) are the gases that produce in the air when the paint dries. As a result of exposure to VOCs, you may get short-term and even long-term health problems, such as headaches, dizziness, respiratory diseases, or liver damage.

          As interior paint is designed for indoor usage, most interior paints have low VOC and you may also find no-VOC interior paint.

Which is more durable: Exterior Paint or Interior?

If you want to use interior paint outside, you may be wondering how durable it is. And which of them is more long-lasting when you apply it outdoors?

The longevity of your paint mostly depends on the surface you are painting and the quality of the paint you are using. Generally, interior paint lasts between 5 to 10 years.

Exterior paint lasts from 5 to 7 years. The environment the painted surface in, and the type of used paint will affect the lifespan of exterior paint.

But these facts don’t mean that using interior paint on an exterior surface lasts longer. 

Buying the right paint gives you the long durability of exterior paint on exterior surfaces. You can get the most lifespan from using exterior acrylic paint. Whereas water-based, latex and oil-based paints last less.

The steps to follow to make exterior paint more durable:

·        Choose a lighter color. Dark colors will fade faster. Lighter colors make outdoor paint last 5 years longer than expected.

·        Before applying the second coat, wait till the paint is cured. You should let the paint dry completely before applying a second coat. This helps to make the life of exterior paint longer.

·        Your preparation should be proper. Before painting, you should focus on the surface that should be painted. If there is dust or dirt, clean them up by washing them. And let them dry. Then make sure whether the exterior surface is ready to paint or not.

·        Keep in mind the climate.

One of the biggest factors that affect the lifespan of the paint is the climate. Sunlight, UV rays, humidity, high or low temperature, snow, and rain decrease the life of exterior paint. So, be sure to choose the paint which can resist environmental hazards.

·        Consider the surface you are painting on.

While painting you should consider the type of material you are painting. According to their type, the paint lasts about 20 years or over on some materials such as aluminum and vinyl.

Can You Use Interior Paint outside?

The question is: ‘Why you are going to use interior paint outside?’

The possible answer may be: it is cheap. Or it is leftover paint, or you like the color of the interior paint of your room or some other reason.

Whatever reason you have, the answer to the question ‘Can You Use Interior Paint Outside?’ is you can, but you should not.

The first reason is interior paints and exterior paints differ because of their additives.

Interior paints have different elements than exterior paints. They can`t resist rain, snow, fading, or high temperature.  So they will be damaged easily on exterior surfaces and don’t last long.

Even if your interior paint is the best one with the highest quality, you can’t use it on outdoor surfaces. Because they are for interior usage, not exterior.

  To conclude, we can say that you shouldn’t use interior paint outside. 

Outcomes of using Interior Paint outside by chance

You may use interior paint on exterior surfaces accidentally, because of not aware of the differences. Or choosing the wrong paint. There is no need to panic. Using interior paint outside doesn’t destroy your house. 

It just means you will probably repaint the surface in two or four years instead of five to ten years.

Interior paint protects the surfaces within a building. But they do not resist environmental hazards. Interior paints will fade quickly. And they don’t have additives to protect against high or low temperatures, UV rays, and other natural disasters.

If you have already painted the outdoors with interior paint, you can paint over the exterior paint. Or you may wait and repaint it in the next year or two.

If you have just begun your painting, you can change the interior paint to exterior paint. And paint over the surface painted using interior paint with exterior paint.

Can You paint over Exterior Paint with Interior Paint?

 According to the additives, types, and lifespan, interior paint and exterior paint are not the same. If you want to paint over exterior paint with interior paint, you can apply it. But you should consider some facts.

Using interior paint over exterior paint demands prep work. And you should use a primer if you are applying water-based paint over oil-based paint.

Keep in mind the additives, interior paint doesn’t consist of the elements that will help to withstand environmental problems.

At first, you can save money as interior paint is cheaper than exterior paint. But in fact, Interior paint doesn’t last as long as exterior surfaces on outdoor surfaces. So you will need to apply for another coat sooner than the warranty time.  As a result, you will spend more money and time.

So we don`t recommend using interior paint for exterior surfaces.

Can you convert Interior Paint into Exterior Paint?

While painting you may ask a question: Can I make interior paint into exterior paint?

The answer is yes. You could mix interior paint and exterior paint.

 It might be a better decision. Because going to the store and buying extra cans of exterior paint may cost and take time. 

But if you have already decided to use a mixture of two types of paints together, you should be aware of some aspects of their usage.

With the information given below, you will understand better how you can mix them.

You can mix two types of paints with different finishes, but it may affect their shine. For instance, when you mix semi-gloss and satin paint, you notice a small drop in the shine of the mixture.

The result of mixing eggshell and matte or satin will be the same. Mixing the paints with completely different finishes like matte and high-gloss, you can’t get great results. But you can use them to do smaller painting projects.

To get better results, you can mix your paints with something similar to the original color and finish.

The best option for exterior surfaces.  

Paints come in two basic types:  oil-based and water-based. For exterior paint, water-based paint is the best option. Because they are more reliable in different environments.

Water-based paints have such benefits:

  • Withstands in different weather.
  • Humidity resistance.
  • Dry quickly.
  • Easy to apply.

The paints designed for exterior usage contain additives that provide long-term reliability. Those addictives provide paints to withstand cracking, damage, UV rays, and other environmental hazards.

Final thoughts.

Every type of paint is for a specific surface. Interior paint is designed to use inside. You can use interior paint outside, but it won’t last long due to weather extremes and you will have to repaint the surface sooner than expected.

If you use interior paint outside, it won’t last and will produce cracks, and UV rays, rain, and snow will easily damage it.

Keep in mind that paints look the best when you use them as they are formulated.

We hope, now, you have a better understanding of interior paint and the outcomes of using interior paint outside.


How long will interior paint last outside?

There are lots of factors to find out how long your paint lasts such as the quality of the paint and the surface. Generally, the longevity of interior paints is from 5 to 10 years. Exterior paint lasts between 5 to 7 years.
But the used interior paint outside doesn’t last as expected. Rain, snow, humidity, UV lighting, and other regional climate conditions damage the outdoor surface. You have to repaint the outdoor surface in a year or two if you have already applied interior paint.

What happens if you use interior paint outside?

It isn’t so serious problem. It means the surface will be likely repainted sooner than expected.
Any kind of interior paint will not withstand snow, rain, UV rays, and other environmental hazards. The main reason is interior paint is designed for indoor usage.

As a result of using interior paint outside, the paint will fade, and crack quickly on exterior surfaces. Then you should repaint the surface in two to five years instead of five to ten.

Is there any difference between indoor and outdoor paints?

The answer is yes. The main difference is their formulation.
Interior paint withstands rain, snow, or other weather changes. But exterior paint is.
And their additives also differ.

The exterior paint may include harmful additives, like VOCs. Interior paint doesn’t have harmful elements as it is for indoor use.

Which is more durable when used outdoors?

The answer is the exterior paint.

The exterior paint is usually more durable than the interior paint. Because exterior paint withstands weather conditions.

And none of the interior paint will not withstand weather fluctuations long enough on exterior walls.