Midi is the most useful dress length and the most misunderstood, because it describes a range rather than a measurement.
Midi is a length, not a style, and that single fact explains most of the confusion around it. A satin bias midi and a ribbed knit midi share nothing except the point at which they stop, and yet both are sold under the same word.
The word covers roughly everything between the bottom of the knee and the top of the ankle. That is a range of about ten inches, which is why two dresses both described as midi can look entirely different on the same person. Understanding where within that range a dress falls is more useful than any other piece of information about it.
Where a Midi Dress Actually Hits
The standard definition is mid-calf, somewhere between the knee and the ankle. In practice most midi dresses land between five and ten inches below the knee.
Because midi is defined relative to the calf rather than as a fixed measurement, the same dress is a midi on one person and close to a maxi on another. A dress with a stated length of 45 inches will sit at mid-calf on someone of average height and considerably lower on someone shorter. This is why the number in the product description matters more than the word.
Measure from your shoulder to the point on your calf where you want the hem. Write it down. It is the single most useful number to have when buying dresses online, and it converts every vague product description into a yes or a no.
The Rule About the Calf
The hem of a midi dress should end at the narrowest part of the calf, which is usually a few inches below the widest point and a few inches above the ankle.
This is not an aesthetic preference. A hem ending at the widest point of the calf makes the leg below it read as shorter and the whole silhouette as heavier, and it does so regardless of the quality of the dress. A hem ending at the narrow point does the opposite. The difference on the same dress is two or three inches of fabric and it is the difference between a dress you wear and a dress you keep meaning to wear.
Shortening a midi hem is a straightforward alteration on any straight or A-line skirt. It is more involved on a bias cut or a tiered skirt, where the hem may need to be taken up from a seam higher in the garment. Ask before you buy if the dress is expensive.
Midi, Mini, Maxi
For clarity, since the three words are used loosely.
Mini ends above the knee. Midi ends between the knee and the ankle. Maxi ends at or near the floor. A dress ending exactly at the knee is usually described as knee length rather than midi, and it is the least forgiving of all the lengths because it draws a line at the widest point of the leg.
Tea length, a term still used for occasion wear, sits at the shorter end of the midi range, typically just below the knee. Ballerina length sits at the longer end, at the ankle.
The number in the product description tells you more than the word midi ever will.
The Shapes and What They Are For
A-Line Midi
Fitted above the waist, widening in a straight line to the hem. The most versatile of the group and the most forgiving, because the skirt never touches the hip. Works for the office, for a wedding, and for a Tuesday.
Bias Cut Midi
Cut diagonally across the fabric so the skirt falls in a fluid spiral. It follows the body closely and moves beautifully, and it is the most demanding to wear because it shows everything underneath it. In satin it is an evening dress. In a matte crepe it is considerably more everyday.
Shirt Dress Midi
Button front, collar, usually a belt or tie at the waist. The most useful midi for daytime because it is genuinely adjustable, and the shape that takes a flat shoe best.
Sheath Midi
Straight and close through the body with minimal flare. The most formal of the day shapes and the one that most needs the hem to be exactly right, because there is no volume to distract from it.
Tiered Midi
Horizontal panels of gathered fabric. Soft, forgiving and summery. The thing to watch is where the tier seams fall, because a seam at the widest part of the hip does the same job as a badly placed hem.
Knit Midi
Ribbed or fine gauge, usually with a defined waist. The winter workhorse. It will grow in length with wear, so buy it slightly shorter than feels right.
Shoes, Which Decide the Outfit
A midi dress leaves a specific window of leg visible, and the shoe closes it or opens it.
A heel, even a low block, lengthens the visible leg and is the reason a midi that looks flat with sneakers looks entirely different with a shoe. A pointed toe does some of the same work without the height.
A flat sandal works in summer with bare legs, because the skin is continuous from hem to foot. A flat shoe with an opaque tight works when the tight matches the shoe closely enough to read as one line.
A knee boot with a midi is the reliable winter answer, leaving a narrow gap between hem and boot. An ankle boot needs a matching tight or the leg is cut into three sections.
What to Wear on Top
The layer above a midi should stop at the waist or hang open at the front. A jacket ending at the hip, over a dress ending at mid-calf, creates three horizontal lines down the body and none of them help.
A long coat over a midi is the exception and it always works, provided the coat is longer than the dress. If the coat hem sits within an inch or two of the dress hem, it will look like an accident.
Hemming and Care
If you buy one midi dress this year, budget for having it hemmed. On a straight or A-line skirt it is a quick and inexpensive alteration, and it converts a dress that is nearly right into one that is exactly right.
Bias cut and tiered skirts are the exceptions. A bias hem has to be shortened carefully and left to hang before it is cut, so allow the alterations shop a week rather than a day. A tiered skirt is usually shortened by removing a tier rather than trimming the hem, which changes the proportion, so ask before you commit.
Store a midi hanging rather than folded if the fabric creases, and folded rather than hanging if it is knitted. A satin midi wants a padded hanger and space either side, since satin takes the mark of whatever it is pressed against.
Midi Dresses Worth Owning
Common Questions
How Long Is a Midi Dress?
Most midi dresses fall between five and ten inches below the knee, which on someone of average height usually means a total garment length of around 40 to 48 inches from the shoulder. Because midi is defined relative to the calf rather than as a fixed measurement, the same dress can be a midi on one person and close to ankle length on another. Check the stated length in inches rather than relying on the word.
What Does Midi Dress Mean?
Midi is a shortening of middle and refers to the middle of the three standard dress lengths. Mini ends above the knee, midi ends between the knee and the ankle, and maxi ends at or near the floor. The word tells you nothing about the cut, fabric or formality of the dress, only where it stops.
The Short Version
Measure from your shoulder to the narrow point of your calf and use that number when you shop. Choose the shape for the occasion rather than the length, since the length is doing the same thing in every case. Keep the layer above it at the waist or open at the front, and let the shoe close the gap at the bottom. A midi that fits is the most useful dress you will own.