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Vintage yarn calculator: ounces to modern balls
Vintage patterns list yarn by weight, usually in ounces (“9 oz 3-ply”). Today we buy by the ball and compare by length. Enter the amount from your pattern and the yarn weight, and we’ll estimate how many metres that was and how many modern balls to buy. If you’re knitting a different size from the one quoted, we can adjust for that too.
Work out your yarn
Typical length per 100 g (wool)
| Yarn weight | Metres per 100 g | Yards per 100 g | Metres per 1 oz |
|---|
How this works, and its limits
- 1 ounce is 28.35 g. We multiply the pattern’s weight of yarn by the typical metres per 100 g for wool of that thickness, which gives a range rather than one exact figure.
- Length per gram depends on fibre as well as thickness. Cotton, linen, silk and some alpaca are heavier, so the same weight goes less far. Acrylic and some lofty wools are lighter, so it goes further. Use the length from your new ball band, not the grams.
- Balls to buy: we take the middle of the estimated range, round up to whole balls and add one spare. If you can, buy from one dye lot and check the shop’s returns policy for unopened balls.
- Size adjustment: yarn use follows the area of fabric. We assume the width of the garment grows in step with your bust, and the length grows about half as much (because lengths change less than widths between sizes). This is a rough guide. Long sleeves, longer bodies or a different fit will change it.
- Some “2-ply” yarns, such as Shetland jumper weight, are much thicker than a fine 2-ply and give about 400–450 m per 100 g, like a 4-ply. If your pattern’s tension is around 28 stitches per 10 cm, choose 4-ply here.
- Published charts disagree, especially for 3-ply (some say 400–500 m per 100 g, others 500–600), so we use a wide range.
- Vintage yardage isn’t standardised, and the pattern’s own amount was for the yarn it was designed for. Treat these figures as a starting point, not a guarantee.
Want a vintage pattern already rewritten for your size and gauge? Browse our patterns. For more on reading old yarn quantities, read our guide to vintage yarn amounts.