In short: a sewing pattern size chart matches body measurements (bust, waist, hip) to a pattern size. You read it measurement by measurement, not as a block: each measurement puts you on a row, and those rows rarely coincide. You then choose the size of the area that decides (the bust for a top, the hips for a bottom). Between two sizes, take the larger one for a fitted garment in a stable woven, the smaller one for a loose garment or a knit. And when your areas fall on different sizes, you grade between sizes. The only chart that counts is the one for your pattern: every pattern company has its own.
What is a sewing pattern size chart?
It's the table supplied with every pattern: on the left, the sizes (34, 36, 38… in French numbering, or S, M, L); alongside, the body measurements each size covers. These are not the dimensions of the finished garment. Between the two, the pattern adds a margin for comfort and style, ease, which changes with the style and the fabric.
Every pattern company starts from its own reference body, then grades it: it enlarges and reduces it from one size to the next according to its own increments. Two practical consequences:
- the same size doesn't have the same measurements from one company to another: a 38 from one may correspond to a 40 from another;
- the step between two sizes isn't always regular, even within one chart: it may grow in the larger sizes, or differ between bust and hips.
Hence the basic rule: never carry over a size from another pattern, nor your shop size. Go back to your measurements and the chart in front of you.
Ready to go from reading to sewing?
Create a pattern to my measurementsWhat does a size chart contain, column by column?
| Column | What it measures | What it's for |
|---|---|---|
| Bust | the fullest part of the bust | choosing the size of a top, dress or jacket |
| Waist | the narrowest part of the waist | adjusting the waistband and darts |
| Hip | the fullest part of the hips and seat | choosing the size of a skirt or trousers |
| Height, back length (if given) | the height the pattern is drafted for | knowing whether you'll need to lengthen or shorten |
| Finished garment measurements (if given) | the dimensions of the sewn garment | reading the ease built into the style |
Watch out for the hip column: the "hip" in a commercial size chart is the fullest measurement, at the level of the seat. Compare it with your seat measurement, not with the hip measurement in our body measurements, which is taken higher up, on the hip bones.
When the pattern also gives finished garment measurements, it's a gold mine: the difference between the finished measurement and the body measurement is the style's ease. Our ease calculator does this calculation for you and tells you whether the garment will be fitted, comfortable or loose.
How do you read a size chart, in four steps?
- Take your measurements with a tape measure, flat against the body, without pulling tight, following our guide to taking your measurements. Don't add ease: the chart gives body measurements.
- Place each measurement in its column: either it lands exactly on a size, or between two sizes.
- Identify the area that decides for the garment you're sewing (see the table further down).
- Cut the size for that area, then grade towards the other sizes if your areas don't fall on the same row.
Here is an example chart, built to illustrate the method. It isn't any pattern company's actual sizing: the numbers on your pattern will be different, and they are the ones that count.
| Size (example, French numbering) | Bust | Waist | Hip |
|---|---|---|---|
| 34 | 80 cm | 62 cm | 86 cm |
| 36 | 84 cm | 66 cm | 90 cm |
| 38 | 88 cm | 70 cm | 94 cm |
| 40 | 92 cm | 74 cm | 98 cm |
| 42 | 96 cm | 78 cm | 102 cm |
| 44 | 100 cm | 84 cm | 108 cm |
Notice that, even in this example, the step changes at the top of the chart: waist and hips grow more between 42 and 44 than between the earlier sizes. Always read the numbers, never an assumed step.
Which area decides, by garment?
You choose the size on the area that's hardest to alter; the more forgiving areas are adjusted afterwards.
| Garment | Area that decides | What you adjust afterwards |
|---|---|---|
| Top, shirt, blouse | bust (and shoulders) | waist, length |
| Jacket, coat | bust (and shoulders) | waist, hips, sleeve length |
| Dress | bust at the top | waist and hips, by grading between sizes |
| Skirt | hips | waist (darts, waistband) |
| Trousers, shorts | hips | waist, leg length |
Why the bust and shoulders for a top? Because shoulders that are too wide or too narrow mean altering the armhole, the collar and the sleeve all at once, whereas a waist can be taken in at the darts or side seams.
Between sizes on a sewing pattern: which should you choose?
It's the most common case. The answer depends on the cut and fabric of the style:
| Your situation | Size to cut | Why |
|---|---|---|
| Fitted garment, stable woven (poplin, canvas, wool suiting) | the larger of the two | the fabric has no give: you keep room to move, and it's easier to take away than to add |
| Loose garment, relaxed cut | the smaller of the two | the style already includes plenty of ease |
| Stretch knit (jersey, sweatshirt fleece) | the smaller of the two | knits stretch and follow the body |
| You're right in the middle and unsure | the larger, then a fitting | you take in at the fitting, you can't enlarge after cutting |
Two precautions before deciding:
- Look at the style's ease. If the pattern gives finished garment measurements, compare them with yours: a very loose style forgives taking the smaller size, a close-fitting one much less so.
- Make a toile for a fitted garment: a trial in an inexpensive fabric shows straight away whether the chosen size sits right at the shoulders and bust.
How do you grade between sizes?
When your areas fall on different sizes, you don't pick a single size: you move from one line to another on the pattern. Let's take the example chart again for a sewist who measures 88 cm at the bust, 70 cm at the waist and 102 cm at the hips, and who is sewing a dress:
| Measurement | What the example chart says |
|---|---|
| Bust 88 cm | size 38 |
| Waist 70 cm | size 38 |
| Hip 102 cm | size 42 |
The bust decides for a dress, so start from the 38. Step by step:
- Follow the size 38 line from the neckline to below the armhole, on both front and back.
- Along the side seam, draw a smooth curve that leaves the size 38 line below the armhole and joins the size 42 line at hip level.
- Transfer exactly the same line to the front and the back, so the side seams stay the same length.
- Keep the size 42 hem from the hips down.
The blend happens on the side seam and doesn't show once it's sewn. For trousers, it's the other way round: start from the hip size and grade towards the waist size, adjusting the darts and waistband if needed.
Nobody is "a size 38". You're a 38 at the bust, a 42 at the hips, and a back length all your own. The size chart isn't a verdict on your body: it's a starting point you adjust.
What if my measurements are off the chart?
If one of your measurements is beyond the pattern's largest size, don't take "the largest, it'll do": the garment will be too tight in that area. Two routes:
- grade the pattern up beyond its last size, by extending the chart's increments, which takes experience on fitted garments;
- choose a pattern whose size range covers you, or a plus-size pattern drafted directly to your measurements.
Our guide to plus-size sewing covers these cases in detail. Conversely, if you're petite, the question is mostly about lengths (bodice, sleeves, legs), which the chart's reference height helps you anticipate.
Frequently asked questions about size charts
Why is my pattern size bigger than my shop size?
Because the pattern starts from your real measurements, while ready-to-wear labels follow each brand's own sizing. It's common to sew a different size from the one you buy in the shops. The mechanics are explained in why shop-bought clothes never fit you.
Between two sizes, should I size up or down?
Up for a fitted garment in a stable woven, down for a loose garment or a stretch knit. If in doubt, take the larger size on the area that decides and take it in at the fitting.
Does the size chart include ease?
No. It gives body measurements. Ease is added when the pattern is drafted and varies with the style. So never add it to your own measurements before reading the chart.
What if I'm on three different sizes?
That's not unusual. Cut the size for the area that decides, then grade towards the other areas, blending the lines along the side seams.
Are size charts the same for all patterns?
No. Every pattern company has its own reference body and its own increments between sizes. Always check the chart supplied with the pattern you're about to cut.
Should I choose my size by bust or by hips?
It depends on the garment: the bust for a top, a dress or a jacket; the hips for a skirt or trousers.
Or stop choosing between two rows: the studio drafts your pattern directly to your body measurements, seam allowances included, with its sewing instructions. See our made-to-measure patterns.
Cover photo: Anastasiya Doicheva on Unsplash.