Introduction
This guide will give an overview of blazers. It'll cover the basics, inspiration albums, outfit ideas, and buying recommendations at the end. It combines and updates previous guides posted on /r/malefashionadvice.
For more in-depth guides on putting together an overall outfit see the Build an Outfit that Works and Understanding Color guides from the sidebar.
What is a blazer?
A blazer was traditionally a navy single breasted worsted wool jacket with brass buttons. This is a good example from Books Brothers. They are worn with contrasting, non colour matching pants.
Nowadays retailers, fashion brands and many people often use the term blazer to describe a range of different garments with an array of fabrics. What people used to term a sports coats (a catch all for anything like a blazer but not in navy worsted wool) can now be called a blazer. To the horror of menswear diehards and traditionalists.
Recognising this change this guide will be a bit wider and will not solely focus on the navy worsted wool version. However if will not focus on more casual blazers which tend to have non-traditional cuts, fabrics and features. There's another guide for that.
General guidelines and outline
Design elements
Blazers come can be either single or double breasted. Single breasted is the most common and often the safer choice. Especially for a first purchase.
Traditional blazers will have structured shoulders
Like suit jackets blazers come fully lined, half lined and unlined. Lining adds weight, structure, and a bit of warm to a jacket. The warmer the climate you live in consider less lined options.
There's a variety of pocket types. From most casual to formal: patch, ticket, angled, flap and jetted.
Lapels: notched, peaked, shawl. Noteched is the most common lapel type, while peaked offers a more attention grabbing option.
Fit
Shoulder width of the blazer should not be too small to bunch up and not too wide that it overhangs which causes divots.
Chest width should not be too tight to cause pulling which creates an 'X' crease of fabric when buttons are closed. Neither should the fit be too baggy.
A body length which covers your bum with the front quarter length ending around your thumb knuckle is recommended. This length is not the most conservative or formal, nor the more fashion forward. Therefore it should fit in well with modern trends.
Sleeve length should show a bit of cuff, but not too much. Neither should the shirt sleeve be hidden by the blazer sleeve length.
Finally, it should be recognised that some brands blazers fit are more modern/fashion forward than others. This means that, for example, Uniqlo's blazers tend to be shorter in the body and arm. For people with average and above height this may be problematic. For people of short stature this is good.
Fabrics
Worsted wool) - is the most traditional and formal.
Tweed - is suited for fall/winter and heavier. Comes in distinctive patterns.
Flannel - wool or cotton with brushed naps suited for fall/winter.
Linen - breathable, light, and often wrinkles. More of a spring/summer and casual fabric.
Corduroy - a fall/winter fabric with raised grooves called "wales". A recent trend. Closer wales tend to be seen as more modern and in fashion.
Cotton twill - a casual fabric for spring/summer.
Chino cotton - a casual fabric for spring/summer which will often wrinkle similar to chino cloth pants.
Also see these two infographics from RealMenRealStyle: on common sports jacket styles and common blazer styles for further reference.
General guidelines for putting together an outfit
The colours discussed mostly refer to solid colours as patterns introduce a whole new layer of complexity. In general though, most patterned jackets are dominated by one major colour and can be matched in much the same way. Patterns do allow for a lot more freedom as well, breaking up harder colours and allowing for more visually interesting combinations.
As a general rule of thumb, dark jackets and light trousers are the easiest combination to work with. The other way around is a bold look that can very easily look bad done wrong and light-light/dark-dark is certainly the most challenging.
Attention and diligence to the shades of both items involved is crucial - too close and you will create a mess. Too far apart and your outfit risks looking disconnected or disproportionate. A very dark jacket and a very light pair of trousers can make one look unreasonably top-heavy. A good way to fix this is by paying attention to the cut of the jacket - a shorter jacket with more open quarters will alleviate and modernise the look. Good if you want to wear a navy jacket with white trousers, for example.
Colour combinations
Navy Jackets - Album
The classic for a reason. Terribly versatile colour that provides the foundation for all manner of outfits.
Combines well with:
Charcoal - a classic British public school look. Risks looking safe but boring unless the fit and details are more modern.
Med/Light Grey
Khaki - An American business staple.
White - A summery, somewhat preppy style. Shorter and tighter jackets work well.
Brown
Blue Jackets - Album
A much more uncommon and vibrant colour for jackets, it's a bold and rather Italian style that looks good with soft shoulders and slim tailoring. Almost exclusively a summer colour.
Looks good with:
White - perfect #menswear summer look.
Khaki
Grey - Lighter greys work better in my opinion, but a darker grey with a light blue jacket is ok too.
Other blues - Depending on the shade of the jacket - there should be a clear contrast between the two.
Grey/Charcoal Jackets - Album
A versatile option giving it's neutral colour. However if people prefer the top half of the outfit to be the attention grabber they won't like it. Charcoal is more formal than grey out of the two.
Works with:
Other Greys - Charcoal for grey jackets, grey for charcoal jackets. Be careful of going too light in shade.
White/Cream - One of the better combinations available - spring/summer only. Pay close attention to the shades involved - lighter greys are much more preferable. Charcoal is too much.
Khaki - A typical look.
Navy
Brown
Brown Jackets - Album
A somewhat under-appreciated colour, brown is really versatile and great for the autumn/winter seasons. Brown jackets frequently feature heavy fabrics (flannel, tweed) and strong patterning.
Charcoal/Grey
Navy
White - Can be very crisp
Olive - A bolder, more playful combination which reinforces the autumnal/country aesthetic
Other shades of brown - tricky to do well, strong patterns and colours help.
Khaki/Tan/Beige Jackets - Album
Another colour much more suited to the summer, a lightweight (perhaps cotton or linen) tan jacket is pretty easy to combine with other summery trousers.
Works well with:
White/Cream - I think cream is nicer with tan personally.
Grey/Charcoal - Lighter greys go great for a more subdued look. Charcoal can work well too, but beware of your proportions. Heavier fabrics look better with charcoal.
Navy
Brown - darker than the tan of the jackets. Can risk looking stuffy depending on the cut and the style (see Bond)
Olive and other pastels for a bolder approach
Olive/Greens Jackets - Album
An underrated colour for autumn/winter. It's impressively versatile and can look great. Finding the right shade of olive/green is a nightmare though - too strong or vivid and it'll border on ridiculous. Some crossover with brown.
Grey/Charcoal
Navy
Khaki/Beige
Browns- an earthy combination
Black Jackets
Can be mistaken for an orphaned suit jacket and generally not a versatile choice for a first blazer. However can mesh well with darker monochromatic wardrobes.
Where to buy
The below recommendations are from the Your favorite ___ for $___: Blazers and Sportcoats megathread and previous guides and discussions on /r/malefashionadvice.
If you have any more please leave a comment outlining why you recommend them and I can add.
Below $150
$150-$400
Above $1000
A lot of these brands can be found cheaper secondhand or from sample sales. Refer to the Beginner's Guide to Buying Expensive Clothes for Less on that.
Brioni
Borelli
Isaia
Zegna Couture
* Leans more on the casual side.
Further reading and resources
Styleforum’s Working Hierarchical Suiting Quality List. Many of these suiting brands also sell blazers.
A Basic Guide on Casual Blazers for those who want a more casual look, especially with jeans.
/r/navyblazer's sidebar resources for more traditional looks and brands.
The Suit Versatility Matrix (with occasion appropriateness recommendations)
Putting together a balanced and tasteful suit/shirt/tie/pocket square outfit.
Guide: The First Suit has some nice overlap
Which shoes would you wear with a blazer?