Why should I wind yarn into a centre-pull ball?

Centre-pull balls are more stable than skeins and do not roll around as you knit. They also prevent tangling. Most yarn winders create a centre-pull cake that sits flat on a surface. Winding also lets you inspect the yarn for knots or defects before starting your project.

Do I need a swift as well as a ball winder?

If your yarn comes in a hank (a twisted loop), you need a swift or a helpful pair of hands to hold the hank open while you wind it. Without a swift, hanks tangle easily. If your yarn already comes in a pull-skein or ready-wound ball, you can wind directly from that onto your ball winder.

How long does it take to wind a skein?

With a hand-cranked ball winder, expect roughly 50 metres per minute, so a 200m skein takes about 4 minutes. Electric winders are faster. The biggest time investment is setting up the hank on the swift and finding the end to start winding.

Yarn Ball Winder Calculator — Free Yarn & Fibre Tool

How We Calculate This

This calculator estimates the size of the centre-pull cake and the time needed to wind your skeins. Cake dimensions are estimated from the yarn weight, the fibre density and how loosely the cake is wound (its packing fraction).

The formula

Fibre volume = Weight / Yarn density (wool keratin ~1.31 g/cm³)

Cake volume = Fibre volume / Packing fraction (~0.16 for wool, i.e. a wound cake is mostly air, bulk density ~0.21 g/cm³)

Cake diameter from a cylinder with diameter ≈ 1.7 × height: V = π·(d/2)²·h, so d = cube root of (4 × 1.7 × Cake volume / π) and height = d / 1.7

Winding time = Total metres / 50 (at ~50m/min hand-crank winding speed)

A ball winder makes a flat-topped, flat-bottomed cake (a short cylinder), not a sphere — so the calculator reports both cake diameter and height. Cake size is an estimate; real bulk density varies with yarn weight and winding tension.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard yarn weights and gauge. Results may vary with individual tension, yarn brand, and needle size.

Yarn Ball Winder Calculator — Skein to Centre-Pull Ball