Princess Margaret turned 21 in 1951 in a cream Christian Dior ball gown, and she later called it “my favourite dress of all,” as BBC Culture and Harper’s Bazaar both report. The skirt was worked with mother of pearl, beads, sequins and raffia, and Margaret joked that the embroidery looked like potato peelings. When the gown went on show at the V&A in 2019, co-curator Oriole Cullen called it “a very modern choice in 1951 for a very modern princess,” because synthetic materials were unusual on couture meant for a royal occasion.

 

That is the bar I set for a birthday dress. It should be a true party dress, the kind I would never wear to a work dinner, with shine, volume or one big idea you can see from across the room. So every dress in this edit has sequins, crystals, feathers, velvet, satin or a bow doing the work, and I sorted them into sequin minis, statement minis, party midis and gowns.

 

Sequin minis come first, because they are the fastest way to make a short dress feel like an occasion. The Mother of All June Sequins Mini Dress in silver and the David Koma Mini Cami Sequin Dress in burgundy are the two I would try first: the June has a wrapped, uneven hem, and the Koma has a sweetheart cami line that looks good with bare shoulders and a small bag. The ROTATE Sequins Bow Mini Dress runs a long pale blue bow down one side, and the SIMKHAI Emilie Sequin Mini Dress is a clean cornflower blue with a scoop neck. For colour, I like the MILLY Izel Colette in yellow, the Camila Coelho Energia in green and the Kim Shui halter in orange. The Lovers and Friends Isabetta has a fringe hem that swings when you dance, and the HELSI Mimi is hot pink and strapless.

 

My test for sequins is a hug. Sequins scratch the inside of the arm and catch on knits, so in the fitting room I sit down, lift both arms and hug myself before I decide. What I would skip: the long-sleeved ROTATE in dark green for a summer birthday in a crowded bar. Save it for December.

When Paris Hilton turned 21 in 2002, she wore a silver chain-mail halter dress by Julien Macdonald, and Vogue reported that Kendall Jenner wore a near copy to her own 21st in 2016. Fourteen years apart, the dress was still the thing people remembered. That is what a statement mini does: one idea, worn well, and nothing else fighting it.

 

Bows are the friendliest place to start. The ROTATE Velvet Bow Mini Dress pairs a black velvet top with a satin bow that falls past the hem, the self-portrait Green Satin Bow Mini Dress is lime with the bow at the back, and the ROTATE Satin Bow Dress is an ivory halter with a bow at the hip. The LEO LIN Caitlin Bow Mini Dress is purple satin cut wide, so it moves more than it clings.

 

For structure, the Zimmermann Luna Corset Mini Dress has a blush corset over a full skirt, the Alex Perry Longline Cupped Corset Mini Dress is cool grey, and the For Love & Lemons Helena Bustier Mini Dress in red is the most fun of the three. Feathers are the loudest choice: THE ATTICO Mini Feather Dress is white with black feather cuffs, the Bronx Banco Tokyo Feather Mini Dress adds feather cuffs to a printed sequin, and the SANS FAFF Posey Mini Feather Dress puts the feathers at the hem. For a winter birthday, the self-portrait Velvet Mini Dress has a pearl trim at the neckline and the retrofete Kadala Velvet Dress is red with a bow at the hip.

 

Do a cake test with a corset: sit, breathe and eat something before you buy it. What I would skip: a feather hem at a party where everyone stands close together. It will get crushed by the second hour.

The photograph everyone remembers from Studio 54 is Bianca Jagger on a white horse at her birthday in 1977, wearing a red Halston dress. Grazia notes that she later wrote to the Financial Times to say she never rode in; she only sat on the horse for a moment after Steve Rubell brought it in as a surprise. The dress is the part that holds up. Halston, who hosted several of her birthday parties according to i-D, made clothes that moved, and that is the rule I use for a party midi.

 

The HALSTON Spaghetti Strap Fit & Flare Midi Dress is plum Dupioni silk with gold strap hardware and a full skirt, so it is the obvious place to start. The SIMONMILLER Imogen Sequin Midi Dress is chartreuse with a paillette hem that sways, and the Alice + Olivia Delora Sequin Strapless Midi Dress fades from pale blue to yellow with a slit at the side. The MILLY Kait Vines Of Floral Sequins Dress puts blue sequin flowers on black, and the retrofete Ellen Sequin Dress pairs ice blue sequins with a black lace bodice. The Nadine Merabi Nina Dress in bronze metallic and the Camila Coelho Atiena in silver are the two I would wear with the simplest shoe.

 

For something without sequins, the SIMKHAI Augusta Bustier Midi Dress has a black bustier over a white skirt, and the Rebecca Vallance Kai Midi Dress is pale blue with a matching belt. The velvet midis are my pick for a cold night: the Ulla Johnson Astra V-neck Velvet Dress is green and crushed, and the Show Me Your Mumu Ricci is black.

 

The test here is a long step and a spin. If the hem catches or the slit opens higher than you want, try the next size or the next dress. What I would skip: a tight sequin midi with no slit if you plan to dance. You will spend the night taking short steps.

On May 19, 1962, Marilyn Monroe sang Happy Birthday to John F. Kennedy at Madison Square Garden in a flesh-coloured Jean Louis dress covered with more than 2,500 hand-stitched crystals, CBC reported, and Julien’s Auctions said it was so tight that she had to be sewn into it. Nobody needs to go that far for a birthday dinner, but it is a good reminder that a gown is the one dress where more is allowed.

 

The sequin gowns are the closest to that idea. The SIMKHAI Leilani Gown fades from pink to coral, the Zhivago The Shimmer Is A Prism Gown is lime with oversized paillettes and one sleeve, and the PatBO Bossa Sequin Gown is deep green with a V neck. The Bronx Banco Allegra Sequin Gown in gold and the Lovers and Friends Ginger Sequin Gown are for a party with a dance floor. The Georgia Hardinge Novalite Dress Floor Length takes a different route, with gold metallic pleats and long sleeves.

 

Satin and velvet are quieter but just as formal. The SAU LEE Delphine Satin Gown is red with rosettes at the shoulder, the MISHA Alastair Satin Gown is cobalt and backless, and the SIMKHAI Reannon Satin Draped Gown is butter yellow. For velvet, the SAU LEE Lenora Velvet Gown is black with a crystal neckline, the Bronx Banco Florentina Strapless Velvet Gown is burgundy, and the Amanda Uprichard Evianna Gown is cocoa with a high neck.

 

Before you buy a gown, walk up a flight of stairs and sit in a car seat in it, with the shoes on. What I would skip: the ROTATE Sequins Maxi Train Dress for a restaurant birthday. A train belongs at a party with room to move.

I choose in this order. First, how big is the night: a dinner for six, a bar with friends or a party with a dance floor. Then the hemline I can move in, then where I want the shine, whether that is sequins all over, feathers at the cuffs or a bow that does the talking.

 

Then I try the exact shoes, sit, walk and take a photo from the side. A birthday dress should still look like you after the cake, the toasts and the last song. If you want to keep browsing, I also put together Brown Dress Guide and Black Lace Dress.