What temperature does cardboard burn?

  • By: Emma
  • Date: December 2, 2022
  • Time to read: 4 min.

When it comes to fires, we often think of wood burning first. But did you know that cardboard is just as flammable?

In fact, according to the National Fire Protection Association, cardboard is the fourth leading cause of house fires. So what temperature does cardboard burn? 

While the answer may surprise you, it’s essential to know to keep your home safe.

What temperature does cardboard burn?

The cardboard is sturdy and has an excellent heat-absorbing capacity. It does not burn until temperatures reach 600-800oF. The flashpoint of cardboard (800oF) is much higher than that of paper (451oF) because cardboard is thicker, has high density, and is a better heat insulator. 

ProductCelluloseHemi celluloseLigninCalcium carbonate
Table 1: Chemical properties of paper and Cardboard.

The science behind burning: how and why things burn

When you see something burning, it looks like a solid object is disappearing. But what’s happening is that the molecules in the object are being broken apart by heat and turned into gases.

The process of burning is a chemical reaction between a fuel and an oxidant. The fuel is usually a solid or liquid, and the oxidant is usually the oxygen in the air.

The molecules in the fuel are held together by chemical bonds. When these bonds are broken, energy is released through heat and light.

Breaking bonds requires a lot of energy, which is why burning objects are so hot. For the reaction to happen quickly enough to be seen, there has to be a lot of oxygen available to react with the fuel.

For example, things burn better in the open air than underwater.

ProductFlash point
Paper451 oF
Cardboard800 oF
Table 2. Flash point of paper and cardboard.

The different types of cardboard and their flammability

Various types of cardboard are available on the market, each with its flammability rating. The most common type of cardboard is corrugated cardboard, made from two layers of kraft paper. This cardboard type is highly flame-resistant and often used in packaging applications.

Another cardboard type is solid bleached sulfate (SBS) board, made from bleached chemical pulp. This type of cardboard has a lower fire resistance than corrugated cardboard and is often used for food packaging or in constructing temporary structures.

Finally, there is unbleached Kraft paperboard made from unbleached chemical pulp. This cardboard type has the lowest fire resistance of all three types and is often used to construct disposable products such as paper plates or cups.

The temperatures at which various types of cardboard will ignite

There are three types of cardboard: corrugated, solid fiber, and paperboard. Each type of cardboard has a different ignition temperature.

1. Corrugated cardboard is made of two liner boards with a fluted board in between them. The fluted board is made of recycled paper and strengthens corrugated cardboard. The ignition temperature for corrugated cardboard is 800 degrees Fahrenheit.

2. Solid fiberboard is made from wood fibers that have been compressed and bonded together with resin. The most common type of solid fiberboard is particle board. The ignition temperature for the particle board is 575 degrees Fahrenheit.

3. Paperboard is a thin, flat material made from recycled paper pulp. Paperboard makes cereal boxes, shoe boxes, and packaging for other products. The ignition temperature for the paperboard is 400 degrees Fahrenheit.

The dangers of burning cardboard indoors

When it comes to burning cardboard indoors, there are several dangers to be aware of.

The first is the release of toxins and chemicals into the air. Burning cardboard releases harmful chemicals into the air, including carbon monoxide and formaldehyde. These chemicals can harm your health and even cause death in high concentrations.

Additionally, burning cardboard produces a large amount of smoke, irritating your lungs and making breathing difficult.

Finally, burning cardboard can start a fire that could quickly spread throughout your home, leading to property damage or even loss of life.

Can you put cardboard in the oven at 170?

Yes, you can put cardboard in the oven at 170 degrees. Cardboard is made of paper, and paper can withstand temperatures up to 400 degrees. So, at 170 degrees, the cardboard will not catch fire. However, the heat will cause the cardboard to degrade and release chemicals that can be harmful if inhaled.

Is it better to burn cardboard or throw it away?

Most people believe throwing away cardboard is better because it takes up landfill space. However, burning cardboard is better because it reduces the methane gas produced.

Methane gas is a greenhouse gas that is twenty-one times more potent than carbon dioxide. When organic materials, like cardboard, decompose in landfills, they produce methane gas. This gas is then released into the atmosphere and contributes to climate change.

Burning cardboard eliminates Methane production because it speeds up the decomposition process. When burned, cardboard breaks down into carbon dioxide and water vapor. These gases are not harmful to the environment like methane gas is. Carbon dioxide is essential for plant growth.


Cardboard is a flammable material and will catch fire at around 800 degrees Fahrenheit. The cardboard will release harmful toxins into the air at high enough temperatures. When burning cardboard, it is important to have proper ventilation to avoid inhaling these toxins.

In conclusion, cardboard is a flammable material that should be carefully burned. High temperatures are required to ignite cardboard, but when it does burn, it releases harmful toxins into the air. Adequate ventilation is necessary to avoid inhaling these toxins when burning cardboard.


Experimental study of burning rates of cardboard box fires near sea level and at high altitude

A study of flame spread in engineered cardboard fuelbeds: Part I: Correlations and observations

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