What Is Semi-Formal Attire?

What does semi-formal mean?

The Emily Post Institute gives the clearest definition. Semi-formal is 'more formal than what you would wear to an office, but slightly less formal than what you would wear to a formal event', and 'if the event is later than 6 in the evening, you'll want to err on the side of formality.' Its list for women runs from a 'Short afternoon or cocktail dress' and a little black dress to a long dressy skirt and top or dressy separates; for men, a dark business suit, dress shirt, tie and leather dress shoes. That overlaps cocktail attire almost entirely, and the Institute says so. Lizzie Post told the Associated Press in 2022 that 'cocktail attire is a subset' of semiformal, a code that runs from 'office holiday parties and charity events to retirement parties and milestone birthdays or anniversaries.' What semi-formal adds is daytime. Emily Post's wedding table splits it in two: by day a 'Dressy afternoon dress, suit, or pantsuit' and, for men, 'Blazer, grey flannels, tie'; by evening a 'Cocktail dress, dressy pantsuit' and a dark suit. The word is American. Debrett's doesn't use it, and a British card that wants a suit and tie says 'lounge suits'. The rungs were busier once: a V&A label lists 1950s Paris dressing as afternoon dresses, cocktail dresses, 'semi-evening (robes demi-soir)' and short evening dresses, distinctions that 'became simpler as the decade progressed'.

Where semi-formal sits on the ladder

Semi-formal for women

1. 
   01

   Navy knee-length sheath dress

   Emily Post's semi-formal list opens with a 'Short afternoon or cocktail dress', and the Posts' 2022 rundown names knee-length among semiformal hems. A plain sheath works at a 2 p.m. christening and, with heels and earrings, at a 7 p.m. party.

2. 
   02

   Burgundy dressy pantsuit

   Emily Post's wedding table lists a pantsuit for daytime semiformal and a 'dressy pantsuit' for evening. In burgundy rather than office navy or grey, it reads as a party suit, not a work one.

3. 
   03

   Champagne satin maxi skirt

   Emily Post lists a 'Long dressy skirt and top', and the Posts allow maxi hems that are 'long but not full-on formal gowns'. With a fine black knit on top, the length reads dressy without reaching black-tie territory. At a wedding, wear the same shape in garnet or bottle green: champagne satin photographs bridal beside a white gown.

4. 
   04

   Black silk bow blouse

   Dressy separates close Emily Post's semi-formal list, and the Posts' 2022 rundown pairs dress tops with dress pants. A silk bow blouse over black tailored trousers is that pairing in two pieces you already own for work.

5. 
   05

   Tea-length silk dress in a cornflower-blue floral

   Tea-length is on the Posts' 2022 list of semiformal hems, and Emily Post's daytime wedding column asks for a 'Dressy afternoon dress'. A mid-calf floral in silk suits a noon garden wedding, where a black sheath looks like evening.

6. 
   06

   Small black evening bag

   Debrett's advice for British lounge-suits events, the nearest UK equivalent, is to replace 'your everyday handbag with a small evening bag'. It's the cheapest way to move an office outfit up to semi-formal.

Semi-formal for men

1. 01

   Dark business suit

   First on Emily Post's semi-formal list for men, with a matching vest marked optional. Choose charcoal or navy: in her business guidance, 'The darker the suit, the more formal.'

2. 02

   Dress shirt and tie

   Emily Post lists 'Tie' plainly under semi-formal and marks it optional only on the dressy casual and business casual rungs. Debrett's adds that you can take it off if the room is looser.

3. 03

   Blazer with grey flannels

   Emily Post's daytime semiformal wedding column: 'Blazer, grey flannels, tie.' It's the daytime alternative to the full suit, and wrong after dark, when her evening column asks for a dark suit.

4. 04

   Leather dress shoes and dark socks

   Last line of Emily Post's list, and the only shoe it names. Polished black or dark brown leather with dark socks keeps the line of the suit unbroken.

Semi-formal in winter and summer

Winter. Chicago's December averages 3°C/37°F by day and −4°C/25°F at night, New York's 7°C/45°F (NOAA). Zola's Maggy Lehmicke says a cocktail or semi-formal request in the colder months means 'you're welcome to pick a more casual option than what you'd choose for a black-tie event', and that a long dress is 'likely expected'. A long dressy skirt and top or a dressy pantsuit under a dark wool coat covers it.

Summer. New York's July averages 29°C/84°F by day and 21°C/70°F at night (NOAA). Emily Post's lists don't change with the season, so lighten the fabric, not the code: a tea-length or knee-length dress in silk or cotton, and a lighter suit with the tie. Debrett's adds that you can remove the tie and undo your top button if the room turns out more relaxed.

Reading the invitation

• “Semi-formal or semiformal” — Emily Post spells it both ways. A cocktail dress or dressy separates; a dark suit and tie.
• “Cocktail attire” — Its evening subset, in Lizzie Post's 2022 words: the same dresses, at the party end of the code.
• “Creative semiformal” — The Posts' 2022 label for a themed card such as 'diamonds and denim' or 'dressy Western': the semi-formal base with the theme on top.
• “Lounge suits” — The nearest British wording. Debrett's says it means 'a suit worn with a shirt and tie', and that it 'is only seen on invitations'.

A suggested look — navy sleeveless knee-length sheath dress, black leather block-heel pumps, pearl studs.

What to avoid

• jeans — Emily Post lists 'Nice jeans and dressy top' under dressy casual, a rung below semi-formal
• a full formal gown — the Posts' 2022 rundown allows maxi hems 'long but not full-on formal gowns'
• a daytime outfit at an evening event — Emily Post says to 'err on the side of formality' after 6 p.m.
• skipping the tie — Emily Post's semi-formal list includes it, and Debrett's says a tie is easy to remove if the room is more casual than you expected
• a big work bag — Debrett's tells women dressing up office clothes to swap the everyday handbag for a small evening bag