A blazer works when it looks chosen, not borrowed: shoulders that sit on your own shoulders, a front that buttons without pulling, and something simple underneath. Get those three right and a blazer is the hardest-working jacket a man owns — it smartens jeans, finishes chinos and stands in for a suit across most of British working and social life. Get them wrong and no outfit underneath will rescue it. Here is the whole subject, in the order it matters.
First, the fit — because nothing else compensates
- Shoulders. The seam should end where your shoulder ends. Unlike knitwear, a blazer's shoulder does not relax into shape; if it overhangs on day one it overhangs forever.
- Buttoning. Fastened, the front should close without an X of creases pulling from the button. If it pulls, it is too small — blazers are not meant to be worn as a squeeze.
- Length. The hem should cover most of the seat and end around the knuckles of a relaxed hand. To ground this in a real garment: our Bedford Herringbone Blazer (£160) measures 73cm in S rising to 79cm in XXL — that gentle rise with size is what a properly graded jacket looks like.
- Sleeves. A sliver of shirt cuff — roughly a centimetre — showing below the sleeve is the traditional mark of a jacket that fits.
The Bedford's own advice applies across the range: regular fit, and if you are between sizes, size up for a relaxed fit rather than down for a tight one.
Structured or unstructured?
This is the real fork in blazer buying, and it decides where the jacket can go.
A structured blazer has a shaped shoulder and a lined, held-together body. It reads as tailoring: right for the office, weddings, dinners — anywhere a suit would not look out of place. The Bedford is this kind of jacket: a single-breasted herringbone weave in a cotton blend, notch lapel, two patch pockets and a chest pocket.
An unstructured blazer drops the padding and lining and behaves more like a cardigan with lapels. Our Kingston (£119) is the type exactly: an unlined cotton-linen blend with a slub texture, a soft shoulder and patch pockets, which its product page says "wears as easily as an overshirt". Choose unstructured for travel, summer and relaxed offices; choose structured when the room is more formal than you are.
What to wear underneath
Keep the layer below quieter than the jacket:
- A roll neck in a dark colour under a textured blazer — the Bedford over a black or navy roll neck with dark jeans is the single easiest smart outfit in this guide.
- A knitted polo or fine crew neck for smart-casual offices.
- A shirt, no tie for anything business-facing. Add the tie only when the occasion plainly asks for it.
- A plain T-shirt under an unstructured blazer only — under a structured jacket it reads as a mistake rather than a choice.
What to wear it with
Chinos and tailored trousers are the natural partners; dark, unripped jeans are the casual one. The one pairing to avoid is a blazer with matching-formality trousers in a nearly-but-not-quite matching cloth — either wear a suit, or make the contrast between jacket and trouser clearly deliberate (herringbone jacket, plain charcoal trousers; navy blazer, grey trousers).
Shoes follow the jacket's formality: loafers or Chelsea boots under structured tailoring, clean minimal trainers under an unstructured blazer at the weekend.
The three-blazer wardrobe
Most men need at most three, and our blazers collection (£119–£279) covers the pattern:
- The textured all-rounder — a herringbone or check single-breasted blazer (the Bedford, £160, in Grey or Brown) for work and dinners.
- The unstructured traveller — the Kingston (£119, in Oatmeal, Navy, Charcoal or Tobacco) for flights, summer and soft-shoulder days.
- The evening piece — velvet. The Mayfair Shawl Lapel Velvet Dinner Jacket (£169, Burgundy or Navy) is a single-button, slim-cut dinner jacket with a black satin shawl lapel — a party-season garment, not an office one, and all the better for knowing it.
Beyond those sit the specialists: corduroy, denim and leather blazers (the St Ives Leather Blazer, £279), each a second-jacket purchase rather than a first.
Where a blazer sits in the dress codes
Smart casual is the blazer's native habitat — our smart casual guide places it at the centre of the code. For weddings and formal winter occasions, a blazer is the guest's jacket, not the groom's: the full-suit end of the question is covered in our tweed and three-piece suits guide.
The short version
Shoulders exact, front closing cleanly, something quiet underneath, contrast rather than near-match below. Structured for formal rooms, unstructured for everywhere else. Browse men's blazers and the wider tailoring collection: UK delivery is free — dispatched in 1–2 working days, delivered in 3–5 working days — with 30-day returns.
Frequently asked questions
Should a blazer be tight or loose?
Neither. It should close without pulling and sit on the shoulder without overhang. The Bedford's guidance is typical: regular fit, and size up rather than down if you are between sizes.
Can you wear a blazer with jeans?
Yes — dark, plain jeans with no rips or fading, and shoes a step smarter than trainers unless the blazer is unstructured. It is the most reliable smart-casual combination there is.
What is an unstructured blazer?
A blazer without the internal padding and lining of traditional tailoring: a soft shoulder, a body that drapes like knitwear, and a much more relaxed feel. The Kingston (£119) is unlined in a cotton-linen blend.
How long should a blazer be?
Long enough to cover most of the seat. On the Bedford that is 73cm in S rising to 79cm in XXL — a useful benchmark if you are comparing jackets.
What's the difference between a blazer and a suit jacket?
A suit jacket is one half of a matched pair and looks orphaned without its trousers; a blazer is cut and cloth-chosen to stand alone — texture, patch pockets and contrast buttons are the usual tells.
