Kettle vs Flask – Difference Between Kettle and Flask

A kettle and a flask are two of the common household items which are majorly used for kitchen purposes. Though kettle and flask have a similar purpose, they are two completely different devices with several differences between them. Many companies such as Prestige and Milton sell kettles and flasks in several different variants, depending upon their capacities, their types, and the time for how long they can insulate the heat of the liquid that is filled inside them.

Kettle vs Flask

The main difference between a kettle and a flask is that a kettle is a specialized jar with an in-built heating system that is commonly used to boil water. On the other hand, a flask is a type of bottle that can keep water maintain its temperature from the time it was put in the flask for about 6 hours to 12 hours.

Kettle and Flask

Electric kettles are the ones that use electricity as the source of getting heated. In most general cases, electric kettles have a power rating of about a minimum of 2-kilowatt to a maximum of 3-kilowatt. Electric kettles are more convenient compared to stovetop kettles as they can be used anywhere without needing a stove.

A flask is known by several other names as well, such as thermos, vacuum flask, Dewar flask, Dewar thermos, and more. The word Dewar signifies the name of the person who first invented a flask, that is, Sir James Dewar. The physical appearance of a flask is like any other common water bottle, and the body of the flask is made up of stainless steel.

Comparison Table Between Kettle and Flask

Parameters of comparisonKettleFlask
Purpose A kettle is generally used to boil water. A flask is used to insulate the temperature of the water.
RequirementsTo operate a kettle, electricity or an external source of heat is required. No electricity or external source of heat is required in the case of a flask.
Also known asA kettle is also known as a tea kettle. A flask is also known as a thermos.
ShapeA kettle is in the shape of a jar. A flask is in the shape of a bottle.
HandleA kettle has a handle. A flask does not have a handle.

What is a Kettle?

In the early decades, a kettle was not an electric device, but just a kind of utensil that was operated by putting it over a heat source, such as the stove. But in current times, a kettle is used as an electric device which works when the cord of the kettle is connected to an electrical outlet. Depending upon the purposes of a kettle, it can be divided into several different categories, such as stove top kettle, electric kettle, whistling kettle, tea kettle, and more.

A stovetop kettle, as the name suggests, is a type of kettle which is operated by putting them over the stove. These kettles do not work on electricity as their source to get heated. Instead, they are traditional types of kettles that are used by putting them over the stove.

Whistling kettles are also known as steam kettles. As the name suggests, these kettles make a whistling sound when they are being operated, that is to say when they are getting heated. When water or any other liquid is filled inside the kettle, and it is either kept on the stove or connected to electricity, the kettle starts to get heated. 

As the kettle gets heated, the temperature of the water inside the kettle also increases. After a certain point, steam starts to form which escaped from an opening in the lid of the kettle. The escape action of the steam creates the whistling sound.

What is a Flask?

The basic purpose of a flask is to store water or any other beverage inside at a constant temperature. In most general cases, a flask can store hot water at a constant temperature for about a minimum of 10 hours to a maximum of 12 hours. On the other hand, a flask can store cold water at its constant temperature for about a minimum of 6 hours to a maximum of 10 hours. 

The basic principle behind the working of a flask and its insulation technique is the use of a vacuum to reduce the loss of heat through the process of conduction and convection. A flask generally has two separate layers inside it. The gap between the outer body and the first layer of the flask has a vacuum inside it. The inner space of the flask is kept free, where the water or beverage is stored.

In today’s time, the flask is commonly used in almost every household, such as to store cold water while traveling during summers, or to store hot beverages, such as tea or coffee during winters. It is also used when one has to store any liquid or beverage in an airtight container, completely away from exposure to the atmosphere.

Main Differences Between Kettle and Flask

  1. Arthur Leslie Large invented the kettle. On the other hand, the flask is invented by Sir James Dewar.
  2. The kettle was invented in the year 1892. Whereas, the flask was invented in 1891.
  3. A kettle is generally available in 1.5 liters capacity. On the other hand, a flask is available in many capacities, such as 500 ml, 1 liter, and 2 liters.
  4. A kettle does not have any cover. On the contrary, a flask has an insulating cover.
  5. A kettle is generally bigger as compared to the size of a flask. On the contrary, a flask is generally smaller in size as compared to the size of a kettle.


A kettle and a flask have many dissimilarities in them. A kettle is a jar-shaped electric device that is majorly used to boil water, however, it has several different purposes too. In many countries, a kettle is used to make tea as well, because which it is known as a tea kettle as well. On the other hand, a flask is a storage bottle that insulates the temperature of the water for a specific duration of time.


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