A garment size is only as good as the measurements behind it. Most knitting patterns are drafted from a small set of body measurements, and a few centimetres in the wrong place can move you into a different size.
Measure over light clothing, stand naturally, keep the tape level, and do not pull it tight. If you can, ask someone to help; reaching around your own back tends to twist the tape.
The measurements that matter
| Measurement | Where | Tip |
|---|---|---|
| Bust / chest | Fullest part, under the arms | Keep the tape level around the back |
| Waist | Natural waist, the narrowest point | Do not hold your breath or suck in |
| Hip | Fullest part, usually about 20 cm below the waist | Stand with feet together |
| Upper arm | Fullest part of the upper arm | Arm relaxed at the side |
| Arm length | Shoulder point to wrist | Arm slightly bent, as if wearing the garment |
| Back length | Nape of the neck to waist | Useful for cardigans and shaped backs |
| Shoulder width | Shoulder point to shoulder point | A helper makes this more accurate |
| Head circumference | Above the ears, widest part | For hats; negative ease is added later |
| Foot length | Heel to longest toe | Stand on a piece of paper and mark it |
How to take each one
Bust. Wrap the tape around the fullest part of the chest and under the arms. Check in a mirror that the tape is level at the back. Keep it snug but not tight.
Waist. Find the natural waist by bending sideways; the crease is usually the narrowest point. Measure there without pulling the tape in.
Hip. Measure the fullest part, usually around the seat. Keep the tape level and your feet together.
Upper arm. Measure the fullest part with the arm relaxed. This is the measurement that decides sleeve width; a tight sleeve is uncomfortable even when the body fits.
Arm length. Measure from the shoulder point to the wrist with the arm slightly bent. A straight arm measurement can produce a sleeve that feels short when you move.
Head and foot. For hats, measure above the ears. For socks, stand on paper and mark the heel and the longest toe; do not measure a shoe size and convert.
A worked example
Bust 96 cm, waist 80 cm, hip 100 cm. A pattern with sizes based on the bust would put you in the size that covers 96 cm, then use the waist and hip measurements to decide whether to shape the body.
If the pattern is close-fitting and your hip is 100 cm, check the finished hip measurement before choosing a size. The bust size may be right while the hip is tight.
Body measurements vs finished measurements
Body measurements describe you. Finished measurements describe the garment after ease is added. A 96 cm bust with 8 cm of positive ease is a 104 cm finished chest. Do not enter the finished measurement into a size chart that expects a body measurement, or the garment will be one size too large.
Children and growing bodies
Measure children close to the project start, and add a little more ease than you would for an adult. A garment that fits exactly today may not fit in three months. Record the date with the measurements.
Limits
Measurements change with posture, clothing and the time of day. Take them twice if the numbers look unusual, and compare with a garment you already own. A tape measure is a guide, not a guarantee of fit.
Once you have the numbers, compare them with the intended ease, then turn the widths into stitches with the cast-on calculator.