yes or noToday we’re going to talk about gaskets and seals. These terms are generally used interchangeably. After all, gaskets seal a joint…so they’re the same, aren’t they?

We want to get your thoughts on the matter. We invite you to take a break from reading and answer the poll below. Don’t worry the results are anonymous…and try to avoid the temptation to scan the rest of the article before answering!


Is there a difference between gaskets and seals?
309 votes · 309 answers


Thanks for taking the time to vote in our poll. Read on for the facts about gaskets and seals.

Gaskets vs. Seals

The terms “gaskets” and “seals” are often used interchangeably. The fundamental difference is that a gasket is a physical piece that goes between two flanges to create a seal at a joining point between two components. A gasket is a seal. “Seals” is a category that encompasses many types of seals. In addition to gaskets, there are rotary seals, O-ring seals, liquid sealants, mechanical seals, shaft seals, valve stem seals, and packings, just to name a few.


Generally, seals require more machining for the sealing surfaces, and a controlled size or quantity of seal material to make it up. They are typically “engineered” as a solution and designed up front.

“Seals” are also terms noted for non-gasket applications, such as rotary shaft seals. These are a dynamic joint and not something that a flat flange gasket is able to seal.


Gaskets generally function with two flat flanges and the gasket material and construction can sometimes be chosen later in the design stages. Various material constructions are available and must be selected to correlate with the available flanges and parameters.

Now You Know

This has been a very general explanation of this topic, but hopefully it has provided some insight into a basic definition of sealing mechanisms. Back to the trivia question…we admit, it was sort of a trick question. A gasket is a seal, but a seal isn’t necessarily a gasket.

Now it is time to stump your friends. Just make sure they at least know what a gasket is before you pose the question! If you are interested in subscribing to Sealed-In’s blog posts, email