A dress needs eight body measurements: bust, waist, hip, back waist length, shoulder width, arm length, bicep and height, plus the length you want from the waist to the hem. Take them in the underwear you will wear with the dress, standing naturally, with a string tied around your natural waist and a soft tape held level and snug but not tight. The bust, waist and hip set the width of each section; the back waist length, shoulder width and arm length put the seams in the right place.
What do you need before you measure?
A soft tape measure, a piece of string or narrow elastic for the waist, a full-length mirror, a pen and, ideally, a helper for the back and shoulder measurements. If you measure alone, a mirror and a little masking tape stand in for the helper. Wear the bra you plan to wear under the dress, because the bust measurement moves by 2 to 4 cm (3/4 to 1 5/8 in) between bras.
Tie the string around your natural waist: bend sideways, and the crease that forms is the level. Most of the vertical measurements start or end at this string, so leave it on until you have finished.
Which measurements does a dress need?
| Measurement | Where | What it decides |
|---|---|---|
| Bust | Around the fullest part of the bust, level | Width of the bodice at bust level, dart size |
| Waist | Around the string | Width at the waist seam, dart intake |
| Hip | Around the fullest part of the seat, feet together | Width of the skirt at the hip |
| Back waist length | From the bone at the base of the neck to the string, down the spine | Position of the waist seam |
| Shoulder width | From the base of the neck to the shoulder bone, along the top of the shoulder | Length of the shoulder seam, armhole position |
| Arm length | From the shoulder bone over a bent elbow to the wrist bone | Sleeve length |
| Bicep | Around the fullest part of the upper arm | Sleeve width |
| Height | Barefoot against a wall | Proportions and default lengths |
| Dress length | From the string at the side down to the hem you want | Skirt length |
The figure on the body measurements page shows where each sits, and the guide to taking body measurements walks through the full set, one measurement at a time.
How do you measure the bust, waist and hip?
Bust. Run the tape around the fullest part of the bust, over the nipples, and check in the mirror that it is level at the back, not riding up under the shoulder blades. Breathe out normally and read the tape snug, not compressing. It is also worth taking the high bust, around the chest above the bust and under the arms: if your bust is more than 5 cm (2 in) larger than your high bust, the bust versus high bust post explains why a standard size chosen by the high bust and then adjusted fits better than one chosen by the bust.
Waist. Around the string, level, with your stomach relaxed.
Hip. Feet together, around the fullest part of the seat, usually 18 to 23 cm (7 to 9 in) below the waist. Check the level from the side. Note how far below the string it is: the pattern places the hip line there.
How do you measure the back waist length?
Drop your chin to find the bone that sticks out at the base of the back of your neck. Hold the tape end there and run it straight down the spine to the string. On most adults it is between 38 and 45 cm (15 and 17 3/4 in). It is the measurement that decides whether the waist seam of a dress sits on your waist or floats above it, and it is the one most often wrong when a dress "fits everywhere but feels off". A bodice that is too short pulls up at the waist seam and strains across the bust; one that is too long bags above the waist.
Take the front length as a check: from the point where the shoulder meets the neck, over the bust point, down to the string. A pattern uses the difference between the two to place the bust dart.
How do you measure the shoulder width and arm length?
Shoulder width. Feel for the bone at the end of your shoulder, where the arm joins; raise your arm slightly and a hollow appears just inside it. Measure from the base of the neck, where a necklace would sit, along the top of the shoulder to that bone. 11 to 14 cm (4 3/8 to 5 1/2 in) is typical. Some patterns want the across-shoulder width instead, from bone to bone across the back; measure both and note which is which.
Arm length. Bend your elbow slightly and rest your hand on your hip. Measure from the shoulder bone, over the outside of the elbow, to the wrist bone. The bend adds the length a straight arm would otherwise lack when you move. For a three-quarter or short sleeve, measure from the shoulder bone to where you want the sleeve to end as well.
Bicep. Around the fullest part of the upper arm with the arm relaxed at your side. A sleeve needs 3 to 5 cm (1 1/4 to 2 in) more than this to move; if you have a full upper arm and the pattern's sleeve is tight, the full bicep adjustment adds width without changing the armhole.
How do you measure the dress length?
Decide where you want the hem: above the knee, at the knee, mid-calf or ankle. Stand straight and measure from the string at the side of your waist down to that point, in the shoes you will wear. For a dress without a waist seam, such as a shift, measure from the base of the neck at the back straight down to the hem instead; a shift dress pattern is cut as one length. For a dress with a waist seam and a fuller skirt, such as a fit-and-flare dress, the skirt length from the waist is the number to give.
How do you measure your height?
Barefoot, heels against the wall, looking straight ahead. Rest a book flat on your head against the wall, mark under it and measure from the floor. A pattern uses height to proportion the lengths you have not measured and to decide the default position of the knee and the hem.
What are the common mistakes?
- A tape that slopes down at the back on the bust and hip. Look in the mirror side on each time.
- Pulling the tape tight to get a smaller number. The dress is drafted with ease on top of your measurement; a tight tape makes a tight dress.
- Measuring over a thick bra or a sweater. Wear what goes under the dress.
- Starting the back waist length at the hairline rather than at the bone at the base of the neck. It adds 5 cm (2 in) and drops the waist seam.
- Measuring the arm straight. Bend the elbow or the sleeve comes up short.
- Adding ease yourself. Give the body measurement; the pattern adds the ease that suits the style.
Sewly's measuring assistant asks for this same set, explains each one on screen and checks the numbers before drafting; a few of them (height, bust, waist, hip) are enough to start and the rest can be refined later. Whichever pattern you use, a dress is the garment where the back waist length and the shoulder width pay you back most, so take those two twice.