How Do I Find My Size in Evening Dresses?

TELLAR FASHION HUB — DRESSES & FIT GUIDES

By Ella Blake, Tellar Stylist

Finding your size in an evening dress comes down to three measurements: bust, waist, and hips — and knowing which one to prioritise for the particular style you're buying. Unlike a casual day dress where a bit of looseness is fine, evening dresses are structured, often lined, and cut to sit precisely on the body. Getting the sizing wrong here is genuinely costly — both in money and in pre-event panic.

Why Evening Dress Sizing Is So Confusing

I have a very clear memory of ordering a floor-length gown for a black-tie wedding in my usual size 12. It arrived, I put it on, and the bodice was so tight I could barely breathe — while the hips pooled around me like a velvet puddle. That was the day I truly understood that evening dress sizing is essentially a different language entirely.

The issue is this: most eveningwear is not made with stretch fabric. A bodycon cocktail dress in jersey will forgive you; a structured satin column gown will not. Evening dress sizing also tends to run small — particularly in occasionwear brands — because the expectation is that you'll have the dress altered to fit. Tailoring isn't a luxury in eveningwear, it's practically a given.

There's also the issue of international sizing. Many evening and bridal brands size in US, EU, or even their own proprietary numbers, which bear almost no resemblance to UK high-street sizing. A US size 8 is roughly a UK 12, an EU 38 is also roughly a UK 10 — but it varies enormously by brand.

The Three Measurements You Must Take

Before you order anything, grab a soft measuring tape and note down all three of these:

Bust: Measure around the fullest part of your chest, keeping the tape parallel to the floor. Wear the bra or strapless solution you intend to wear with the dress — this genuinely changes the measurement.
Waist: Measure around your natural waist — the narrowest point of your torso, usually a couple of inches above your belly button. Don't suck in; breathe normally and measure.
Hips: Measure around the fullest part of your hips and seat, roughly 7–9 inches below your natural waist. Stand with your feet together for accuracy.

Now write all three down in centimetres and compare them against the brand's size guide — not the UK number, the actual centimetre measurements. This is the single most important step, and most people skip it.

Which Measurement to Prioritise by Dress Style

This is where it gets a little more nuanced, and where knowing your dress style saves you a lot of grief:

Fitted/column/bodycon styles — size for your largest measurement. If your hips are a size 14 but your bust is a 12, order the 14 and have the top taken in. It's much easier to take in than to let out.
A-line or fit-and-flare — prioritise your bust and waist; the skirt flares from the hip so there's usually more room below.
Empire waist or floaty styles — bust is the most critical measurement here, as the dress falls loose from just under the bust.
Wrap styles — these are the most forgiving; size for your bust and the waist ties adjust to fit.
Strapless or sweetheart necklines — your underbust measurement matters as much as your bust here; a too-large strapless bodice will simply fall down mid-evening. Not ideal.

High Street: Best Picks for Evening Sizing

The high street has genuinely stepped up for eveningwear, and a few brands are particularly reliable when it comes to consistent sizing:

Monsoon — consistently one of the best high-street options for occasion dresses; their sizing is accurate and they cater well to sizes 6–24. Their size guides are detailed and trustworthy.
Coast — specifically designed around occasionwear; their fit is tailored and sizing tends to run true. Always worth checking the cm measurements on their site.
Phase Eight — brilliant for structured, grown-up eveningwear. Their dresses are well-lined and size consistently; a reliable choice if you can't try before you buy.
Hobbs — polished and precise; great for formal occasions where you need something that looks quietly expensive. Sizing is true and their fit is cut for adult proportions.
ASOS — huge selection and very useful if you're petite, tall, or plus-size, as they offer dedicated ranges. Size up if in doubt; returns are easy.
Anthropologie — gorgeous, feminine occasion dresses; their sizing leans US so always convert carefully. Their detail is exceptional for the price point.
River Island — brilliant for trend-led occasionwear at an accessible price point. Sizing can vary by style, so check reviews; stretch fabric styles are more forgiving than structured ones.

Premium & Designer: Where to Invest

For a truly special occasion — a wedding, a milestone birthday, a gala — it's worth considering a premium or designer option. The construction quality makes a real difference to how a dress fits and moves:

Reiss — impeccably cut occasionwear at a premium high-street price. Their evening styles are structured and elegant; sizing is precise so measure carefully before ordering.
LK Bennett — the gold standard for smart occasions in the UK. Beautiful fabrication and consistent sizing; a favourite for races, weddings, and formal events. Their fit is cut for women with curves.
Ted Baker — known for gorgeous floral and embellished occasionwear. Note that Ted Baker historically used its own sizing (0–5 rather than UK numbers) — always cross-reference with their measurement chart.
Claudie Pierlot — French brand with beautiful, feminine evening separates and dresses. Sizing runs small by UK standards; I'd always size up one here.
Max Mara — investment-level occasionwear with extraordinary fabric and cut. Runs true to European sizing; expect to pay for alterations to get the fit perfect, but it's worth every penny.

Two Independent Brands Worth Discovering

Rixo — one of the most beloved independent British dress brands right now, adored by Vogue editors and real women in equal measure. Their vintage-inspired silk and chiffon styles are stunning for evening; sizing is true but their detailed measurement guides make ordering online straightforward.
Needle & Thread — ethereally beautiful embellished and tulle styles that look extraordinary on. They're a genuinely independent British brand; sizing runs true and their size guides are unusually accurate and detailed.

The Alteration Question — and Why You Shouldn't Fear It

I'll say this clearly: buying an evening dress that fits perfectly off the rail without any alteration is the exception, not the rule. Most women's bodies don't conform to the proportions that dress patterns are graded to — and that's not a problem, it's just reality. A good tailor can take in a bodice, shorten a hem, or take up straps for £20–£60 depending on the complexity. For a dress you're spending £100+ on, it's absolutely worth factoring in.

If the dress fits your largest measurement and needs adjusting elsewhere, a tailor can usually fix it easily. What a tailor cannot easily fix is a dress that's too small — so when in doubt, always size up.

Get Your Exact Size Across 1,500+ Brands — Free

Evening dress sizing is genuinely one of the trickiest areas to navigate because brands vary so wildly. That's exactly the problem Tellar.co.uk was built to solve. It's the UK's leading free sizing tool — you enter your measurements once and it instantly matches you to the right size across 1,500+ brands. No more cross-referencing size guides, no more returns.

Measure once — bust, waist, hips, or an existing size you know fits
Use the Store Size Lookup tool to find your exact size in any brand — whether that's Coast, Phase Eight, LK Bennett, ASOS, or a smaller independent label
Always free — no app, no subscription, works instantly in your browser

The Tellar Fashion Hub is also packed with free, honest, unbiased style content — from fabric guides to body shape advice. No ads, no sponsorships, no agenda.