The Difference Between a Blazer, a Suit Jacket and a Sportcoat
Most of us are usually unaware of the basic difference between 3 of the most essential outerwear for gentlemen i-e (Blazers, Suit Jacket and Sport Coat). Here’s a guide on basic differentials between the three.
 
The Blazer:
Blazer, Casual Jacket, Jacket
  • Trademark for the members of the boating clubs.
  • Can be pulled off with a jeans, hard to carry with brass bottoms
  • Traditionally has brass/metal buttons, but that’s obviously not always the case now.
  • Looks best in solid colors, almost always navy.
  • Wool blazers always adds a traditional value.
  • Lies in between Sport coat which is more casual and Suit jacket which is formal.

The Sport coat:
Sportcoat, Sports jacket
  • Usually an outerwear to carry with suits.
  • Sometimes, people tend to use the term blazers when referring to Sport coats(traditionalists hate this, since most of the people think it's not a big deal)
  • Fabrics are usually cotton or linen
  • More casual in nature than blazer
  • Originally worn at sport events or activities (hunting, shooting etc.

Suit Jacket, Suits, Jacket
  • A mismatched combination with jeans.
  • Buttons are usually made of horn or plastic
  • Fabrics are usually more finer and smoother than sport coats
  • Looks best with matching trousers.
  • More constructed in nature (Shoulder, canvas, pads etc)
 
If a jacket doesn’t have a matching pants, it is safe to term that as blazer or sport coat. If it has matching pants then it will definitely be termed as suit jacket. Whereas, if it's not navy in color or has gold buttons, then it's a blazer.