Between two sizes: how to read a size chart before you trust a letter
Bust, waist and hip, taken once with a tape, and what to do when the three numbers land in two letters. Which fabrics forgive, which do not, and how a set, a jumpsuit and a bikini each break the rule in their own way.
A parcel on the bed at eleven at night
The box is the wrong letter. You know the dress will not be the dress you pictured when you ordered it. It is a real moment. The seams do not lie and the hem hits in a place you did not expect. The top is almost right but it gaps at the bust and pulls across the waist. Everyone has stood in the kitchen in the same socks and considered the options. Toss it. Keep it. Exchange it.
First, pause. Take the garment off the hanger and hold it level beside something you already wear, not a model in a photo. Look for the obvious signs where fit is stubborn: the bust gapes, the waistband puckers, the skirt clings. Those are the spots that will tell you whether the wrong letter is a salvage job or a return.
Second, if you plan to exchange, measure. Not the letter you always buy. Not the label you trust from habit. Get the three numbers on your body. Keep them in your phone. That action will save time on the next parcel, and it will stop guessing from becoming the rule. If this is a dress for a wedding in a week, measure now. If it is a piece you want for work every day, measure now and keep the note.
Measurements are the only objective part of a fit problem. They will not solve styling choices. They will solve letters.
The three numbers
Measure standing up straight in front of a mirror. These are not decorative steps. They are how you stop guessing. For the bust, wrap the tape level around the fullest point, over the bra you will wear with the piece. Do not pull the tape tight. It should sit comfortably against the skin but not compress. Record that number.
Find the waist by bending sideways once. Where the body creases is the natural waist, not where your jeans sit. Place the tape there, level all the way around, again without squeezing. Write the number down. Those two numbers will decide the top part of a dress and the fit of a bodysuit.
For the hip, stand with the feet together and wrap the tape around the widest part of the seat. The tape must be level front to back. If you keep these three numbers in your phone, you will be able to read any chart and know at a glance whether the piece is worth trying in your usual letter or whether the fabric and cut demand another decision.
If a chart gives a torso length for a bodysuit or jumpsuit, measure from the hollow at the base of the neck to the point between the legs while standing. That is the number that stops surprises when you sit.
How to read a chart and what a letter promises
Every buying page prints bust, waist and hip in inches for each letter of that piece. A letter is a promise only about that chart. Do not treat an XS on one card as the same as an XS on another card. The numbers are the promise and the letter is the shorthand.
When your three numbers sit squarely inside one letter on the chart, that is the simplest case. Order that letter. When they fall across two letters, the fabric decides for you. Some fabrics give and some fabrics do not. A forgiving fabric will let a smaller letter breathe without altering the line. An unforgiving fabric will make seams pinch, darts pull and zips refuse to close.
Keep the chart open while you look at the photo. Look for notes on fit that appear on the card. If the card says a piece runs small, believe it and size up. If a size is not printed on the card, it is not offered for that piece. That fact saves a wasted order.
A letter is not a lifetime commitment. It is a promise about one chart, one cut and one fabric built into that card on that page.
A letter is a promise only about that chart.
When two letters meet and the fabric breaks the tie
The two-letter problem is common. Your bust might sit in an S while your waist sits in an XS. The deciding factor is fabric and the cut. Knits with ribs, crochet, shirred panels and babydoll cuts forgive a smaller letter because they move as you move. Woven satins, denim, sequin-covered fabrics and faux leather do not forgive. They hold a line and they will reveal if you chose the smaller letter.
If you are between letters and the piece is a MAKEMECHIC Babydoll Sleeveless Swing Mini Dress, remember it has a shirred bodice and spaghetti straps and no stretch in the fabric. It hangs from the bust and that hanging makes it forgiving in the waist. The run is XS to XL, and because the bodice is shirred, the smaller letter is often acceptable without pulling at the hem. Check the chart and the bust measurement first. If the bust is right, the dress will fall as intended.
MAKEMECHIC Babydoll Sleeveless Swing Mini Dress
Sizes XS to XL · 9 colourways · Spaghetti straps
$42.99
For a woven skirt or tailored short where seams and zippers determine the line, pick the larger letter when you are between. A fitted waist does not fake room. Seams will pull and the hem will ride up. If a cut has visible panels or a zip fly, size toward ease. If a piece lists that it runs small on the card, follow that note.
Pay attention to where the garment is meant to sit on the body. A mini that is loose at the bust but tight at the hip will read small at the hem. A top with a cross-over front that lies flat only when the bust fits needs the larger letter to avoid gap. Fabric is the tie-breaker in every two-letter match.
The Plus scale is its own language
The Plus scale is not a continuation of the straight sizes. A 2XL is not the same as a 1XL Plus. The Plus run is marked by the word Plus after the letter, for example 1XL Plus and 3XL Plus. Treat it as a different alphabet. A piece printed with Plus sizes is cut on its own scale, with different shaping and different grading between letters.
When a garment is offered in a Plus run, the card will show the bust, waist and hip in inches for each Plus letter. Read those numbers and compare them to your three measurements. Do not assume you can translate a straight-size letter to Plus by simply moving one up on the rack. Also keep in mind that a piece available only in Plus will have its own design choices, such as longer hems, different sleeve widths and reworked darts.
Every card carries the run the piece is cut in. If a size is missing from the card, it is missing from the piece. That clarity helps you avoid the frustration of ordering something that was never offered in your letter to begin with. For pieces that bridge both scales, the card will list both runs separately and those numbers are what you must compare.
Sets, bikinis and the rule of the half that matters
Two-piece sets and swim are sold as one piece with one letter for both halves. Size for the half that must hold. For a shorts set, take the waistband measurement. For a bikini, size for the bottom more than the top if the bottom fits you less often. A halter top adjusts at the neck and can forgive moving one letter up. In contrast, a triangle top with a fixed underband will not.
The MAKEMECHIC Polka Dot Bikini Set is sized as one letter for both top and bottom. It is a halter neck with a triangle top and a high-cut bottom in a stretch fabric. The sizing runs XXS to XL. When you are between letters, prioritise the piece that will be harder to replace in fit. If your hips run larger relative to your bust, select the letter that fits the bottom. If the bottom gaps and you force the letter smaller for the top, the swimsuit will not stay put.
Bodysuits, jumpsuits and the brutality of torso length
A bodysuit must fit at the bust and at the torso. The chart will carry a torso length. If you are tall through the ribs and waist, you may need to size up so the crotch does not pull and the fabric does not ride. A too-short torso shows when you sit. That small annoyance is obvious and unfixable without an exchange.
Jumpsuits are the same problem twice. They need to fit the bust and the torso and the hip. If your torso is short, the jumpsuit may ride up at the crotch and gather at the waist. If your torso is long, the waist seam will sit lower than expected. Try to match the torso length on the card to a garment you already own that fits well.
A maternity piece is sized by your pre-pregnancy letter. The ease is built into the cut by ruched side seams, stretch panels and empire waists. Trust the pre-pregnancy number and let the design provide room for the change. Bras and bralettes on the lounge rail are sized by letter, not by band and cup, so use your three numbers for those too.
Tailored pieces with no stretch will demand the larger letter when in doubt. That is the practical rule. If a card carries a flag that a piece runs small, obey it. If it names a recommended one-size larger choice for a tailored cut, follow the guidance. The card is the source of truth for that piece.
The tailored short that asks for one size up
The MAKEMECHIC Tailored Plaid High Waisted Shorts have a zip fly, a button front and slant pockets and no stretch in the fabric. They are offered in sizes XS to 2XL, and the card suggests choosing one size larger than usual. That guidance comes from how the fabric behaves on the body.
If you are between letters at the waist, size up for these shorts. The zip and the fly do not forgive a smaller size. If your waist measurement is solidly in the middle of the smaller letter but your hips move you toward the next size, pick the larger letter. The tailoring will preserve the intended silhouette. If you wear these shorts with a tucked top, the waistband must be comfortable when you sit.
If you own a pair of tailored shorts that fit well, measure that waistband and compare it to the numbers on the card. That comparison is the fastest way to decide which letter will keep the tailoring neat without the tug at the seams.
Length, model height and the wardrobe test
A mini on a model is not the same mini on you. Length matters more than we admit. Compare the inch length printed on the chart with a dress or skirt already in your wardrobe. Lay the garment flat and measure from the top of the waistband or shoulder seam to the hem. If the site gives a garment length in inches, match it to your reference piece.
If you are tall, a dress labelled mini may be mid-thigh. If you are shorter, the same length may be above the knee. That difference changes how a hem lands in relation to a shoe and it changes the overall balance of a silhouette when you walk. For a piece with non-stretch fabric and a hem that hits high on the thigh, consider whether the length will be comfortable and appropriate for the occasion.
Pay attention to where the model wears the piece in the image. The rise of a skirt and the placement of a waistband can shift the visual height by a couple of inches. If a card lists inseam or rise for shorts or trousers, measure a pair you already own and compare. That exercise is a small work of accuracy that prevents surprises.
The body is not the problem
A wrong letter is not a failure of the body, and the exchange happens at the till where the payment was taken. Returns and exchanges are tools, not confessions. Use them. Measure first. Use the numbers on the card. When in doubt because of fabric, pick the larger letter for non-stretch wovens and the smaller letter may be acceptable for ribbed knits, crochet and shirred or babydoll cuts.
Fit is a problem-solving exercise. It has rules you can learn and steps you can follow. Take the measurements. Read the chart. Let the fabric have the casting vote when letters collide. The rest is style, which you already know how to decide.
| Kind of piece | What to measure first | Which way to size when between letters |
|---|---|---|
| Tops and dresses | Bust over the bra you will wear with the piece | Forgiving fabrics: smaller letter may work. Unforgiving fabrics: choose larger letter |
| Bottoms and skirts | Hip with feet together | Choose larger letter for woven, no-stretch pieces |
| Two-piece sets and bikinis | The half that must hold (waist for shorts, bottom for swim) | Size to the half that matters. halter tops may allow one size up |
| Bodysuits | Bust and torso length | Size for torso if chart shows a torso length. size up if torso is long |
| Jumpsuits | Torso length then hip | Size up if torso or hip measurements demand it |
| Maternity pieces | Your pre-pregnancy letter measurements | Use pre-pregnancy letter. room is built into the cut |
More of this sort of thing is in The Edit, and the MAKEMECHIC studio keeps the whole range one click away on the front page.