How Do I Find My Size in Midi Dresses?

By Ella Blake, Tellar Stylist | Tellar Fashion Hub

To find your correct size in a midi dress, you need three measurements: your bust, waist and hips — and crucially, you need to size to whichever of those three is largest, then check it against each brand's specific size chart. Midi dresses are one of the trickiest categories to size in, because unlike a top or a pair of jeans, they have to fit across your entire body simultaneously. Get one measurement wrong and the whole silhouette falls apart.

I learnt this the hard way with a gorgeous floral midi from Anthropologie a couple of summers ago. I ordered my usual size — fitted beautifully across the bust and waist — but the skirt sat about four inches too high on my leg, hovering at a deeply unflattering shin-grazing length. A true midi should hit somewhere between the knee and the ankle, ideally at mid-calf. On me (5'6"), that usually means checking the dress length in the product description before I buy, not just defaulting to my usual size. Height matters just as much as your body measurements here.

The Three Measurements You Actually Need

Grab a soft tape measure — the fabric kind used for sewing — and measure the following:

Bust: Around the fullest part of your chest, keeping the tape parallel to the floor. Don't hold your breath or pull the tape tight — it should lie flat but not dig in.
Waist: At the narrowest part of your torso, typically just above your belly button. Breathe normally.
Hips: Around the fullest part of your seat and hips — usually about 8 inches below your natural waist. Stand with feet together for this one.

Write all three down. Then, when you look at a size chart, find the size that accommodates your largest measurement. This is the single most important rule in dress sizing, and it's the one most people ignore.

Why Midi Dresses Are Tricky — And What to Look For

The midi length works beautifully on almost every body type, but the fit varies enormously depending on the cut. There are three main silhouettes to be aware of:

Fitted or bodycon midis: These hug the body all the way down. Size for your hips — full stop. If the hip fits, a tailor can take in the waist, but you cannot create extra room in a stretch fabric that's already at capacity.
Wrap midis: The adjustable waist tie makes these the most forgiving for sizing, but the bust can still catch you out. Make sure the chest isn't pulling across the front — that's a sign you need to go up a size.
A-line and floaty midis: Generally the easiest to size because the skirt has volume and movement. Here, sizing to the bust and waist is usually sufficient, with the skirt taking care of itself.

The Best High Street Brands for Midi Dresses — and How They Size

Not all midi dresses are created equal, and each brand has its own sizing quirks. Here's my honest take on the ones worth knowing:

Phase Eight — consistently brilliant for midi dresses. They do them better than almost anyone on the high street, in my opinion. Their sizing is true to size and the cuts flatter a wide range of body shapes. If you're dressing for a wedding or a smart occasion, start here.
Hobbs — excellent quality, particularly for wrap and fit-and-flare styles. Runs true to size, though the bust can be slightly generous. Good news if you're fuller-busted; size down if you're not.
Mint Velvet — one of my personal favourites for everyday midi dressing. Gorgeous fabrics, relaxed silhouettes, and they size consistently across their range. Great for pear and hourglass shapes.
Cos — sizes in European measurements, so generally a size smaller than UK high street. A UK 12 will often need a COS 38 or 40. Their midis are beautifully minimal and well-constructed.
Jigsaw — reliable, well-cut, and particularly strong for taller women (their standard length works better for longer legs). Sizes true to the UK standard.
Me&Em — slightly premium but outstanding quality. Their jersey midis wash brilliantly and the sizing is consistent. I'd always recommend checking their length guide — they have options for petite, regular and tall within each style.
Oliver Bonas — brilliant for print midis and a younger, more playful aesthetic. Sizes generously, so if you're between sizes, go down.
Great Plains — underrated gem for relaxed, everyday midis. Natural fabrics, consistent sizing, and genuinely flattering cuts without the premium price tag.

Height and Midi Length — The Overlooked Factor

A midi dress is defined by its length, so your height genuinely matters here — perhaps more than for any other dress category.

If you're petite (under 5'4"): A standard midi will likely hit closer to the ankle on you, which can overwhelm a shorter frame. Look for brands with dedicated petite ranges — Next and M&S both have strong petite options — or check the dress length in centimetres before buying. Aim for a hem that hits at or just below mid-calf.
If you're 5'4"–5'7": Standard sizing usually works well. Most brands design their midi lengths with this height range in mind.
If you're tall (5'8"+): A standard midi can end up as more of a knee-length or just-below-knee dress. Boden and Hush both carry tall options, and it's always worth checking if a brand offers a long-length alternative.

What About Fabric — Does It Affect the Size?

Yes, more than people realise. Stretch fabrics — jersey, ponte, elastane blends — have give in them, which means they're more forgiving across measurements. Woven fabrics — cotton, linen, silk, chiffon — have no stretch at all, so you must size more carefully to your exact measurements.

For woven midi dresses, I'd always recommend going by the size chart rather than your usual instinct. Massimo Dutti is excellent for structured woven midis and their size charts are detailed and accurate. Ted Baker — who use their own numbered sizing system (0–5 rather than 6–18) — is worth double-checking every single time; their 3 can correspond to a UK 12 or 14 depending on the style.

Two independent brands genuinely worth knowing: Sézane, the French label beloved by stylists for its beautifully proportioned midi dresses in gorgeous fabrics (their sizing leans French, so generally size up), and Lisou, a UK-based brand doing spectacular printed silk-style midis that have a cult following — sizing is true to UK standard and the quality is exceptional for the price.

A Few Rules I Always Follow

Never size to your waist alone — always cross-reference with bust and hips.
Check the dress length in the product description, not just the size label.
Read the fabric content — it tells you how much (if any) give there will be.
If the brand has a petite, regular or tall option, use it. It makes an enormous difference to how the hem falls.
When in doubt between two sizes in a woven fabric, go up. You can always belt or tuck a midi dress — you can't magic extra room out of thin air.

Find Your Exact Size in Any Brand — Instantly, for Free

This is exactly the kind of sizing headache that Tellar.co.uk was built to solve. Enter your measurements once and Tellar instantly matches your body to the right size across 1,500+ brands — including every brand mentioned in this post. No more guessing, no more returns, no more dresses that are perfect on the bust but pooling at the ankle.

Use the Store Size Lookup tool to get your precise size for specific brands in seconds. It works in-browser, needs no downloads, and it's completely free.

If dresses are your thing, our Ultimate Guide to Dresses, Body Shapes and Where to Shop is essential reading — and if you want to sort your sizing across every category in your wardrobe, the Ultimate Clothing Sizing Guide will walk you through it properly.

The Tellar Fashion Hub is packed with honest, unsponsored style advice from our team of stylists. No ads, no brand partnerships, no hidden agendas — just genuinely useful content, always free.

Ella Blake is a stylist and founder of Tellar.co.uk, the UK's leading free clothing sizing platform covering 1,500+ brands.