Bust EU 42, waist EU 46, hips EU 44 – now what? Hardly any body fits neatly into one column of a size chart. I've seen it for years in every email I get about sizing: "I'm between three sizes, which one do I take?" That is exactly why I built the SEAMONE size calculator. It not only tells you which size to sew, but also what to adjust on your pattern so that it really fits – the way I would do it at the cutting table as a pattern maker.
What makes our size calculator different
Most size calculators compare one measurement with a chart and give you a size. Done. Ours works the way a professional pattern maker would:
- It knows your pattern. You choose the sewing pattern, and it uses exactly that pattern's size chart – from women's patterns in EU 30–60 to men's patterns in EU 44–74.
- It picks the right base size. For tops and dresses the bust counts, for trousers and skirts the hips.
- It calculates your bust adjustment (FBA/SBA). Our patterns are drafted for a B cup. From your full bust and upper bust it works out whether you need a full bust adjustment (FBA) or a small bust adjustment (SBA) – and by how many centimetres. For an FBA it takes the base size from your upper bust, so the shoulders and neckline don't end up too wide. That is where most tops go wrong: they fit at the bust and gape at the shoulders.
- It shows every size you need. If your bust, waist and hips fall into different sizes, you get each one with the difference in centimetres. You then blend smoothly between them – no more than two sizes apart, so the shape stays balanced.
- It adjusts the length. Using your height, it works out how much to lengthen or shorten. Our patterns are based on 168 cm for women and 180 cm for men.
- Trouser tip included. For trousers it reminds you of the crotch curve – a flatter or rounder bottom makes more difference than any size.
How to use it
- Choose your pattern – or "General" if you just want to get your bearings.
- Enter your measurements: full bust, upper bust, waist, hips and your height. The upper bust is optional – but without it the calculator can't work out an FBA/SBA.
- Read your result: base size, bust adjustment, size per measurement, sizes needed and length adjustment.
You'll find the size calculator on every product page, right next to the pattern, and as a page of its own. You can then print just the layers you need from the PDF sewing pattern – only the sizes the calculator names, and nothing else on the paper.
How to measure
The best calculator is no use if the tape measure is crooked. Here's how to measure:
- Measure close to the body over thin, fitted clothing – the tape lies flat but doesn't pull in.
- Full bust: around the fullest part of the bust, keeping the tape level.
- Upper bust: right under the armpits, above the bust, all the way round.
- Waist: at the narrowest point.
- Hips: at the fullest point over the bottom.
Ideally, ask someone to measure you – or measure twice and take the average. And please measure honestly, not hopefully: the pattern will only fit as well as the numbers you type in.
An example
Let's take the measurements from the screenshot above: full bust 106 cm, upper bust 96 cm, waist 88 cm, hips 109 cm, height 162 cm, pattern: a top with our standard size chart. The calculator shows:
- Base size EU 44 – from the upper bust (96 cm + 4 cm), not the full bust.
- FBA: add 3 cm – the difference between full and upper bust is 10 cm instead of 4 cm for a B cup.
- Waist EU 46, hips EU 44 – at the waist you blend gently into one size larger.
- Shorten by 3 cm – 6 cm shorter than 168 cm, and for a top half of that.
Had this sewist simply gone by her full bust and sewn EU 46, the top would have been a whole size too big at the shoulders and neckline. With EU 44 plus an FBA it sits neatly at the top and still has room at the bust. If a measurement falls between two sizes, the calculator picks the larger one. How to sew an FBA, SBA or length change is explained step by step, with drawings, in the instructions for your pattern.
Already got fabric?
Size first, then fabric: once you know which size you're sewing, the Fabric Planner shows you which SEAMONE patterns fit the fabric you have – leftovers included.
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