Yarn unit converter

Yarn labels mix units: 220 yd per 3.5 oz on one ball, 200 m per 100 g on another, Nm 2/28 on a cone. This converter puts them on the same footing so you can compare yarns, and it converts single measurements between inches, centimetres, yards, metres, ounces and grams.

How to use the converter

1. Ball band: enter the label's length and weight, in any units, to get the length per 100 g, per 50 g and per ounce, plus the mill units.
2. One measurement: convert inches, centimetres, yards, metres, ounces or grams.
3. Cone count: enter an Nm count such as 2/28: 2 plies of a yarn with 28 m per gram.

How the converter works

It uses the exact definitions of the units:

1 in = 2.54 cm, 1 yd = 0.9144 m, 1 oz = 28.349523125 g, 1 lb = 453.59237 g

From the label it works out metres per gram (the metric count, Nm), and from that every other figure:

Nm = metres ÷ grams; for a cone, Nm = single-ply count ÷ plies

Tex = 1,000 ÷ Nm (grams per 1,000 m), denier = 9,000 ÷ Nm (grams per 9,000 m)

Yards per pound = yards per gram × 453.59237

It also shows the weight category that the length per 100 g suggests.

Reading your results

• Per 100 g, per 50 g and per ounce: in yards and metres, so you can compare any two labels.
• Typical category: from length per 100 g only. Check the thickness with the wraps per inch calculator.
• Mill units: yards per pound, Nm, tex and denier, the units on cones and weaving yarns.

Worked examples

• 220 yd per 3.5 oz: 3.5 oz is 99.22 g, so the yarn has 221.7 yd (202.7 m) per 100 g, 62.9 yd per ounce and 1,005.7 yards per pound. That is in 3 Light.
• Nm 2/28: 28 ÷ 2 = 14 m per gram, which is 1,400 m (1,531.1 yd) per 100 g and 71.4 tex: a lace-weight cone.
• Comparing two balls: a yarn with 115 m per 50 g has 230 m per 100 g; the 220 yd per 3.5 oz yarn above has 202.7 m. The second yarn is heavier for its length.

Accuracy and limits

• The conversions are exact and covered by our automated tests.
• The category is a guide from length per 100 g only; dense or fluffy fibres can sit in a different category by thickness.
• Cone mode takes metric counts (Nm). Cotton counts (Ne), used on some weaving cotton, are a different system: multiply the Ne number by 1.693 to get Nm first.

Common mistakes

1. Treating yards and metres as equal. A metre is about 9% longer than a yard. Buying 1,500 yd for a pattern that needs 1,500 m leaves you about 128 m (140 yd) short.
2. Multiplying by the plies. Twisting 2 plies of 28 m/g yarn together makes it twice as thick: 14 m per gram, not 56.
3. Reading the cone count the wrong way round. Some mills write 2/28, others 28/2. The smaller number is the plies; the larger is the single-ply count.

Tips for more accurate results

• A quick shortcut in a shop: metres to yards, add about 10% (200 m is about 220 yd); yards to metres, take off about 9%.
• To see what several strands of a fine cone make together, use the yarn held together calculator.

Frequently asked questions