Difference between Aluminum and Stainless Steel

Both aluminum and stainless steel are hard metals that have a wide range of applications. The metals look similar but they are very different in that one is an alloy while the other is not. They are also different in terms of composition, density, strength etc. Knowing the difference can help you determine which one you need for your project or which kitchen appliance you need to buy. Here are a few differences:


Aluminum vs Stainless Steel
Aluminum spoon

Aluminum is a silvery looking metal element that is both light and strong. These properties have led to its wide applications in making certain objects. For example, aluminum is preferred in making car bodies and airplanes.

Stainless Steel
Kitchen Knife Stainless Steel Cutting edge

Stainless steel is a metal alloy consisting of iron and chromium. The amount of chromium combined with iron can vary from 10 percent to 30 percent so as to achieve the desired characteristics of stainless steel. Some other elements such as titanium and nickel may be added to enhance specific qualities of steel.

Comparison Chart

Aluminum Stainless steel
Is an element but not an alloy Alloy of iron and chromium
Lighter and not very strong compared to steel Heavier and stronger than aluminum
Doesn’t give out sparks Gives out sparks when subjected to a grinder
Cheaper Expensive
Less reactive More reactive than aluminum
Cheaper due to simple refining process More expensive than aluminum because it involves a lengthy refining process

Aluminum vs Stainless Steel

What is the difference between aluminum and stainless steel? The difference between them lies in their composition, how they react to air and their uses.

  • To tell the difference between aluminum and stainless steel, most people subject them to a grinder. When subjected to a grinder, things made from aluminum do not give out sparks. Stainless steel items give out a lot of sparks when grinded (see video below).
  • Aluminum is an element. It is not a combination of two elements like in the case of stainless steel. Stainless steel is an alloy metal consisting of chromium and iron. Stainless steel does not rust or corrode easily like other metals. The amount of chromium used varies from 10 to 30 percent. Chromium is used so as to make the metal anti-corrosive and rust resistant. Chromium reacts with air to form an oxide film which protects the steel. Stainless steel has a variety of applications including those found in home and restaurant kitchens for making appliances such as rice cookers and utensils.
  • Aluminum is a bit weaker as compared to stainless steel, but it’s a lot lighter and hence preferred in making aircraft bodies. Stainless steel is very strong and heavy.
  • Aluminum is available cheaply and it does not require much processing. It’s also a good conductor of electricity, hence it is used in making power cables. Aluminum does not rust due to the formation of an oxide coating on its surface. Aluminum is preferred in making boilers and other heating vessels since it does not react with the contents, and conducts heat effectively.
  •  Stainless steel, on the other hand, is expensive due to the lengthy refining process and alloying. In most cost conscious projects such as construction, aluminum is used instead of stainless steel.


Here is a video showing one of the methods of determining if a metal is made from stainless steel or aluminum: