Standard Garment Measurements and Ease

How pattern sizing actually works

A pattern gives two sets of numbers and people routinely read the wrong one.

• To fit chest is a body measurement. It describes you.
• Finished chest is the garment's measurement, flat, after blocking. It describes the sweater.
• The difference between them is ease, and it is a design decision the pattern has made.

If a pattern lists only finished measurements, the ease is yours to decide - which is why knowing your own chest measurement matters more than knowing what size you buy in a shop.

The standard measurements

The Craft Yarn Council publishes standard body measurements that most American patterns are sized against, running from X-Small to 5X. A few reference points from the women's table:

The full standard also gives waist, hip, back waist length, armhole depth and arm length to underarm for every size, with metric equivalents. It is the reference to check when a pattern's sizing looks unusual - a pattern that departs a long way from it is telling you something about its intended fit.

Ease, which is the whole of fit

What to measure, and how

1. Chest or bust, at the fullest point, tape level and snug but not tight. This is the number everything else follows from.
2. Upper arm, at the fullest point. Sleeves are the second most common fit failure.
3. Back waist length, from the bony bump at the base of your neck to your natural waist. It tells you whether to lengthen the body.
4. Arm length to underarm, from wrist to the armpit with the arm relaxed.
5. Cross back, shoulder point to shoulder point across the back.

Measure over the underwear or shirt you would actually wear under the garment, and have someone else hold the tape if you can - self-measuring the back is unreliable.

The shortcut that works better than measuring

Find a sweater you already own and love the fit of. Lay it flat and measure it across the chest, from underarm seam to underarm seam. Double that number.

That is your target finished chest measurement, with the ease already baked in by a garment you have worn and liked. It sidesteps the entire ease question, and it is the single most useful thing in this page.

Where fit goes wrong

• Choosing by size label. Shop sizing and pattern sizing are unrelated. Work from the chest measurement.
• Ignoring gauge. A gauge error of one stitch per four inches puts an adult garment a full size out - the arithmetic is on the gauge page.
• Ignoring upper arm. Many patterns grade sleeves proportionally, which does not suit every body. Compare the pattern's upper arm figure to yours.
• Forgetting the fiber will move. Superwash wool grows; cotton stretches downward; untreated wool blocks to shape and stays. See does wool yarn shrink.
• Not accounting for length. Body and sleeve length are the easiest things to adjust and the most often left at the default.

Adjusting length safely

Length is the one change that requires no re-calculation, which makes it the safe adjustment for a first fitted garment.

Add or remove rows in the straight sections - below the armhole on the body, and below the sleeve cap shaping on the sleeve. Never adjust inside a shaping sequence. Then check your yardage: extra length costs yarn, and the yardage page shows how much.

Children's and men's sizing

The Craft Yarn Council publishes equivalent standard tables for men, children and babies alongside the women's one. The method is identical: measure the chest, add the intended ease, choose the size by finished measurement.

For children the one extra consideration is growth. Two inches of extra length in the body and sleeves buys a year of wear and costs very little yarn.