Black Tie vs White Tie: What Women Wear to Each, With Gowns

The invitation says black tie, the dress in your wardrobe stops at the knee, and you have no idea whether that is a rule broken or a rule kept. White tie turns up once a decade and reads like a different language. Below are the two codes in the words of the two etiquette guides that still define them, the one point where the guides lean differently, and gowns in plus sizes that satisfy each, with September 2026 prices.

The quick answer

Code	What women wear	Length	Where it applies
White tie	Full-length evening dress or ball gown; long gloves may be worn with a sleeveless dress	Floor only	The rarest and most formal invitations
Black tie	Evening dress: knee-length cocktail dress or floor-length gown	Either	Weddings, galas, formal dinners, proms
Black tie optional	Formal gown, shorter cocktail dress or dressy separates	Either	Events that want black tie without insisting
Creative or relaxed black tie	Short or long dress, or evening trousers	Either	Parties that say so on the card

White tie: both guides say floor length

Debrett’s calls it “the most formal event code, and the rarest”, and its instruction for women is one sentence: “Women should wear a full-length evening dress or ball gown, with or without sleeves. Long gloves may be worn with sleeveless dresses.” Emily Post files it as “full evening dress”, “the most formal of all dress codes”, and lists two items for women: “Formal (floor length) evening gown” and “Long gloves (optional)”. The Wikipedia summary adds evening gloves and, optionally, tiaras and a small handbag.

So there is nothing to interpret. Floor length, and a ball gown counts. The difference between a ball gown and an evening gown is the skirt: a ball gown always has a full skirt and a fitted bodice, while an evening gown can be any silhouette, and the structure that holds a full skirt up is in plus size ball gowns.

Black tie: an evening dress, either length

Debrett’s: “Women should wear an evening dress; knee length cocktail dresses are the most popular choice, though floor-length evening dresses can also be worn.” Emily Post’s list for women runs “Formal (floor length) evening gown”, “Dressy cocktail dress”, “Your dressiest ‘little black dress’”, and it calls black tie “the most common formal dress code for events such as weddings, proms, formal dinners, and theatre.”

That is the one place the two guides lean differently. Debrett’s names the knee-length dress as the popular choice; Emily Post puts the gown first. Both allow both, so the choice is yours, and the safer direction on either guide is up rather than down: Debrett’s general rule is that “it’s preferable to look over-, rather than under-dressed.”

Two variants sit beside it. Emily Post’s black tie optional lets women “choose either a formal evening gown, a shorter cocktail dress, or dressy separates”, with men in a tuxedo or a dark suit. Debrett’s relaxed black tie, also called bohemian or creative black tie, means “a woman could opt for short or long dress (or tailored or palazzo style evening trousers).”

Gowns that meet white tie, and black tie too

Floor length in plus sizes, sold without a markdown when read on 20 September 2026:

• Kiyonna Evening Romance Gown, $198, sizes 0X (10-12) to 5X (30-32). Floor-length with a surplice bodice, three-quarter sleeves and a cinched waist; the listing names “black-tie events, formal galas” as its occasions. With sleeves, the gloves question does not arise; Debrett’s pairs long gloves with sleeveless dresses.
• Adrianna Papell Plus Size Long Sleeve Velvet Tuxedo Gown, $249, sizes 14 to 26. A satin shawl collar over a surplice bodice and a column skirt with a high side slit, sold for “black tie galas”. Velvet, so a cooler-months gown.
• Alex Evenings Plus Jersey & Satin Surplice-Neckline Ball Gown, $239, sizes 14W to 24W. A jersey bodice with elbow-length sleeves over a full satin skirt, which is the ball-gown shape white tie was written for.
• Jenny Yoo Rominia, $595, sizes 00 to 32. A strapless A-line in satin jacquard with a ruched, structured bodice, and the widest size run on this page. It is an Anthropologie Weddings exclusive that cannot be tried in Jenny Yoo’s showrooms, so order by the chart.

Dresses that meet black tie at the knee

• Kiyonna Luna Lace Dress, $158, 0X to 5X. Knee-length scalloped lace with a slightly full A-line skirt and a mesh back that hides bra straps, sold as a cocktail dress.
• Adrianna Papell Plus Size Three Quarter Sleeve Stretch Sequin Sheath Dress, $179, sizes 14 to 26. A knee-length sequin sheath with sleeves, described by the brand as a classic cocktail dress.

More gowns by size run and price are in plus size evening gowns, and the knee-length code on its own is in what cocktail attire means.

For the men reading over your shoulder

White tie is a black tailcoat with silk lapels, worn unbuttoned, trousers with two lines of braid, a shirt fastened with studs, a wing collar and a thin white bow tie. Black tie is a black dinner jacket with silk lapels and covered buttons, trousers with a single row of braid, a soft-collared white or cream shirt and a bow tie you tie yourself. Those are Debrett’s specifications. Emily Post’s lists broadly match, with one split: a single stripe of braid on white-tie trousers in the US, two in Europe or the UK; and for black tie in summer, in the tropics or on a cruise, a white dinner jacket replaces the black one.

Before you order

• Read the card, not the venue. Black tie optional and creative black tie are their own codes, and both admit a shorter dress.
• For white tie, floor length is the rule. Long gloves are optional on both guides and traditionally go with a sleeveless dress.
• Take bust, waist and hip before choosing a size, and let the largest one pick the row; gown charts run their own way.
• Check returns before paying. A gown bought for one evening is the purchase you most want to be able to send back.

The other dress-code guides are in events.

Where these numbers come from

The dress-code wording is quoted from Debrett’s “Deconstructing Dress Codes” and Emily Post’s attire guide, with the Wikipedia entries on white tie and evening gowns for the accessories and the ball-gown definition. Prices and size runs are the brands’ own listings on 20 September 2026, in US dollars, limited to items not marked down on that date.

Frequently asked questions

Can a woman wear a short dress to a black tie event?

Yes. Debrett's says knee-length cocktail dresses are the most popular choice for black tie, with floor-length evening dresses also worn, and Emily Post lists a dressy cocktail dress and your dressiest little black dress beside the floor-length gown. Only white tie rules the short dress out.

What is the difference between black tie and white tie for women?

Length. White tie is a full-length evening dress or ball gown on both guides, with long gloves optional for a sleeveless dress. Black tie is an evening dress of either length. For men the difference is a tailcoat with a white bow tie against a dinner jacket with a black one.

What does black tie optional mean?

Emily Post's definition: men are requested to wear a tuxedo but can opt for a dark suit, and women can choose either a formal evening gown, a shorter cocktail dress, or dressy separates. It is black tie with the floor-length option kept and the shorter dress and trousers admitted.