Choose a sewing pattern size from your body measurements, never from the size you buy in shops. Compare your bust, waist and hip with the pattern's body measurement chart, use the bust for tops and dresses and the hip for skirts and trousers, then blend between sizes where your measurements fall in different columns. If you would need three sizes or more, a made-to-measure pattern drafted from your own measurements skips the choice altogether.
Why your shop size is the wrong starting point
Ready-to-wear sizes vary from brand to brand and from country to country, and many have drifted larger over the years. Sewing patterns follow their own body measurement charts, so many sewists find their pattern size is one or two sizes above their shop size. The number on a label tells you nothing until you compare measurements.
EU, US and UK labels also count differently. On Sewly's women's chart, the US size is the EU size minus 32 and the UK size is the EU size minus 28, so EU 38 is US 6 and UK 10. The sewing size converter translates between systems.
Step 1: Take your measurements
Measure at least your height, bust, waist and hip, following how to take body measurements. Wear what you will wear under the garment, and keep the tape level and snug.
Step 2: Find your measurements on the chart
Use the pattern's body measurement chart, not the finished garment measurements (step 4 explains the difference). For reference, these are the body measurements behind Sewly's standard women's sizes:
| EU | US | UK | Bust, cm (in) | Waist, cm (in) | Hip, cm (in) |
|---|---|---|---|---|---|
| 32 | 0 | 4 | 76 (30) | 60 (23 1/2) | 85 (33 1/2) |
| 34 | 2 | 6 | 80 (31 1/2) | 64 (25 1/4) | 89 (35) |
| 36 | 4 | 8 | 84 (33) | 68 (26 3/4) | 93 (36 1/2) |
| 38 | 6 | 10 | 88 (34 3/4) | 72 (28 1/4) | 97 (38 1/4) |
| 40 | 8 | 12 | 92 (36 1/4) | 76 (30) | 101 (39 3/4) |
| 42 | 10 | 14 | 96 (37 3/4) | 80 (31 1/2) | 105 (41 1/4) |
| 44 | 12 | 16 | 100 (39 1/4) | 84 (33) | 109 (43) |
| 46 | 14 | 18 | 106 (41 3/4) | 90 (35 1/2) | 115 (45 1/4) |
| 48 | 16 | 20 | 112 (44) | 96 (37 3/4) | 121 (47 3/4) |
| 50 | 18 | 22 | 118 (46 1/2) | 102 (40 1/4) | 127 (50) |
| 52 | 20 | 24 | 124 (48 3/4) | 108 (42 1/2) | 133 (52 1/4) |
| 54 | 22 | 26 | 130 (51 1/4) | 114 (45) | 139 (54 3/4) |
The steps are 4 cm (1 1/2 in) up to EU 44, then 6 cm (2 3/8 in). The men's sizes:
| Size | Chest, cm (in) | Waist, cm (in) | Hip, cm (in) |
|---|---|---|---|
| XS | 86 (33 3/4) | 74 (29 1/4) | 90 (35 1/2) |
| S | 92 (36 1/4) | 80 (31 1/2) | 95 (37 1/2) |
| M | 98 (38 1/2) | 86 (33 3/4) | 100 (39 1/4) |
| L | 104 (41) | 92 (36 1/4) | 105 (41 1/4) |
| XL | 110 (43 1/4) | 98 (38 1/2) | 110 (43 1/4) |
| XXL | 116 (45 3/4) | 104 (41) | 115 (45 1/4) |
| 3XL | 122 (48) | 110 (43 1/4) | 120 (47 1/4) |
Children's sizes go by age, from 2 years (92 cm, 36 1/4 in tall) to 14 years (164 cm, 64 1/2 in tall). All the charts, with every measurement, are on the size charts page.
Step 3: Pick the measurement that matters for the garment
- Tops, dresses and jackets: choose by bust or chest, because shoulders and necklines are the hardest areas to alter. If your bust is much fuller than the chart's for your frame, a size chosen by the bust can be too wide at the shoulders; choose by the upper chest instead and make a full bust adjustment, a change that adds room over the bust only.
- Skirts, trousers and shorts: choose by hip. A waist is easier to adjust than a hip, with darts, elastic or the side seams.
- Elastic-waist garments: choose by hip, since the waist has to stretch over it.
- Loose and oversized styles: they have plenty of room, so if you are between sizes the smaller one usually works.
- Hats: choose by head circumference only.
Step 4: Check the finished garment measurements
Finished measurements are the size of the garment itself. The difference between the finished and the body measurement is the ease: the room for movement and for the style. If a finished bust is 14 cm (5 1/2 in) more than yours, the top is designed to be loose; that is not a reason to size down.
To picture the fit, hold a tape measure around yourself at the finished measurement, or compare it with a garment you own and like.
Step 5: Blend between sizes
Few bodies match one column exactly. On a multi-size pattern the nested sizes are drawn inside one another, so you can move from one size to another along a piece: for example size 40 at the bust, 42 at the waist and 44 at the hip.
- Mark your size at the bust, waist and hip on each piece.
- Draw a smooth line between the marks over at least 10 cm (4 in), never a sharp step.
- Blend the matching pieces the same way (front and back, facings, waistband, pocket pieces) so the seams still match.
- Walk the seams together and check that the notches still line up.
Step 6: Check the lengths
Pattern sizes assume a height. Sewly's women's sizes are drafted for 168 cm (5 ft 6 in) and the men's for 178 cm (5 ft 10 in); many commercial patterns use similar heights. If you are much shorter or taller, adjust the bodice, sleeve and skirt or trouser lengths before cutting, using your back waist length, arm length and inseam.
Or skip sizes: made to measure
A made-to-measure pattern is drafted from your own measurements, so there is no column to choose and nothing to blend. In Sewly you can pick a standard size (women EU 32–54, US 0–22, UK 4–26; men XS–3XL; children 2–14 years) or enter your measurements. Height, bust, waist and hip are enough to start: the other measurements come from the nearest standard size, scaled to your height and girths, and you can refine any of them while the pattern redraws instantly. Custom-fit sewing patterns explains how it works.
Common mistakes
- Choosing by shop size. Compare measurements, every time.
- Choosing a skirt by the bust. Lower-body garments are sized by the hip.
- Sizing down because the pattern looks big. The extra width may be designed ease. Check the finished measurements first.
- Blending one piece only. The back no longer matches the front. Blend every piece that shares the seam.
- Ignoring height. A correct width at the wrong length still looks wrong; adjust lengths too.