Pattern Size Converter

Convert between womenswear letter sizes, US, UK and European numeric sizes, and the chest, waist and hip measurements each one is drafted for.

Sewing

A US 12, a UK 16 and an EU 40 are the same size, and none of them tells you what your body actually measures. This converter reads across letter sizes, three numeric systems and the body measurements behind them, in inches or centimetres, so you can pick a pattern size from a tape measure rather than from the size you wear in a shop.

At a glance

What you enter: Pattern size, Show measurements in, Which measurement, Your own measurement
What you get: Chest or bust, Waist, Hip, US size, UK size, EU size, Your measurement versus the table
Formula shown: Yes, every step, right below your results.
Cost and privacy: Free, no account needed, and nothing you type is stored.

See worked examples ↓ Read the FAQ ↓ Share this calculator ↓

Pattern size

Womenswear sizes only. Menswear and childrenswear use different tables.

Show measurements in

Which measurement

Pick the measurement the garment is fitted by. A skirt is fitted by the hip, not the waist.

Your own measurement in

Enter your own measurement to find the size index number for it. Leave at zero to use the table figure for the size above.

Reset

Results are estimates for general information only, always verify with a professional or official source before acting on them.

How to use the Pattern Size Converter

1 Enter Pattern size, Womenswear sizes only. Menswear and childrenswear use different tables.
2 Enter Show measurements in
3 Enter Which measurement, Pick the measurement the garment is fitted by. A skirt is fitted by the hip, not the waist.
4 Enter Your own measurement (in), Enter your own measurement to find the size index number for it. Leave at zero to use the table figure for the size above.
5 Press Calculate. You get Chest or bust, Waist, Hip, US size, UK size, EU size, Your measurement versus the table, and every intermediate step stays visible under "How is this calculated?"
6 Change one number at a time to see what moves the result, that is usually the most useful thing a calculator can tell you.

Worked examples

Real numbers run through this calculator. Open any example to load it into the form above and change it.

A UK 16 pattern, shown in centimetres

A size L pattern that is a US 12 and a UK 16, looked up in centimetres.

You enter

Pattern size: 4
Show measurements in: 2
Which measurement: 1
Your own measurement: 0 in

You get

Chest or bust: 95.00 in
Waist: 76.25 in
Hip: 101.25 in
US size: 12
UK size: 16
EU size: 44
Your measurement versus the table: 0.00 in

The centimetre figures are the inch figures times 2.5, so they read like a tape measure rather than a conversion table.

Open this example in the calculator →

Choosing a skirt size by hip measurement

A 42 inch hip, so the calculator finds the closest pattern size for a skirt.

You enter

Pattern size: 4
Show measurements in: 1
Which measurement: 3
Your own measurement: 42 in

You get

Chest or bust: 38.00 in
Waist: 30.50 in
Hip: 40.50 in
US size: 12
UK size: 16
EU size: 44
Your measurement versus the table: 1.50 in

A skirt is chosen by the hip, then the waist is taken in, not the other way round.

Open this example in the calculator →

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Frequently asked questions

What size is a US 12 in UK sizing?

A US 12 is a UK 16 in womenswear, and an EU 44. Pattern sizing is not the same as ready to wear, though: a woman who wears a UK 12 in a shop may well need a pattern UK 16, because pattern blocks are drafted to body measurements rather than to the vanity sizing used in retail. Measure yourself and choose by the chart.

Should I choose a pattern size by my bust or my hip?

Choose by the measurement the garment is fitted by, then adjust the rest. A skirt or trousers should be chosen by the hip, because that is where the fit is decided. A fitted bodice should be chosen by the high bust or the full bust depending on the cup size the pattern is drafted for. Most people grade between two sizes, which is normal rather than a failure of the pattern.

Why do my measurements not match any single size?

Because the size tables describe an average that very few people are. If your bust is a size 14 and your hip is a size 16, cut the pattern in the size that fits your bust and grade out to the larger hip below the waist. That is a standard alteration, and it is why tracing a pattern rather than cutting it is worth the trouble.

How much ease should I add to my measurements?

A woven dress or blouse needs about 3 inches of ease at the bust and 2 inches at the hip beyond your body measurement, which is a comfortable fit. A fitted garment can use 2 inches, and a loose or oversized one 6 inches or more. Knit patterns usually build in negative ease instead, which is why a knit pattern size looks smaller than the equivalent woven one.