Substituting yarn: why two DK yarns need different ball counts

Count metres, not balls

A ball count only means something for the yarn the designer used. Multiply it by that yarn’s metres per ball to get the length you need to replace. Then divide that length by the metres per ball of the yarn you want to use, and round up to a whole ball.

If the pattern already gives metres or yards, start from that. One yard is 0.9144m. The grams-to-metres tool does the conversion from any label, and the yarn library pages list the figures for the yarns we track.

How far apart DK yarns really are

We took the ball weight and length for 17 yarns labelled DK, mostly from the maker’s own product page. We couldn’t load Garnstudio’s own pages, so the three DROPS figures come from Wool Warehouse’s listings. Every figure was checked on 1 October 2026.

The longest were the two baby yarns, Rico Baby Classic dk and Sirdar Snuggly DK, at 330m per 100g. The shortest were DROPS Lima and DROPS Cotton Light at 200m. That is 65% more yarn per gram at the top of the range than at the bottom. The everyday acrylic DKs, such as Special DK, Simply DK, Hayfield Bonus DK and Big Value DK, sit close together between 276m and 295m.

Why the same label hides different lengths

Yarn weight names are defined by thickness and tension, not by length. The Craft Yarn Council puts DK in its category 3, “Light”, with a knitted tension of 21–24 stitches to 10cm (4in) and a suggested hook of 4.5–5.5mm. The table gives no figure for metres per 100g.

The labels bear this out. Stylecraft Special DK at 295m and WYS ColourLab DK at 225m both give a tension of 22 stitches to 10cm. DROPS Lima at 200m gives 21. Fibre is the pattern we saw: every yarn in our table that was mainly cotton, wool or bamboo (including the cotton-polyester DROPS Cotton Light) came in between 200m and 250m per 100g, and every acrylic or nylon-led yarn between 276m and 330m.

Category names on shop sites can mislead too. Hobbii lists its Rainbow Cotton 8/8 as “Light”, the Craft Yarn Council name for the category DK sits in, at 75m per 50g. That works out at 150m per 100g, so it isn’t in our DK table.

Worked example: replacing 6 balls of Special DK

Say a pattern asks for 6 balls of Stylecraft Special DK. At 295m a ball, that’s 6 × 295 = 1,770m. Paintbox Simply DK has 276m a ball: 1,770 ÷ 276 = 6.41, so you buy 7. King Cole Cottonsoft DK has 210m: 1,770 ÷ 210 = 8.43, so you buy 9.

Ball counts jump with 50g balls. DROPS Cotton Light has 100m a ball, so 1,770 ÷ 100 = 17.7, which means 18 balls. That’s 900g, the same weight as the 9 balls of Cottonsoft. Watch yarns near a whole number too: King Cole Merino Blend DK at 104m needs 1,770 ÷ 104 = 17.02, so 18 balls. Seventeen balls would give 1,768m, just 2m short, so one more metre a ball would have saved a whole ball.

Six balls is the designer’s buying quantity, not a measured amount used. We haven’t made this project. The point is the ratio: whatever length the pattern gives, the substitute needs the same length, not the same number of balls.

Same length, heavier project

A lower metres-per-100g figure also means the finished piece weighs more. 1,770m of Special DK weighs 600g. The same length of a 200m-per-100g yarn weighs 885g, nearly half as much again. Check that before you swap an acrylic for a cotton in anything you want to stay light.

A ball-for-ball swap goes wrong in the other direction too. Say a pattern asks for 9 balls of King Cole Cottonsoft DK, which is 1,890m. Nine balls of Special DK hold 2,655m, about 40% more than you need.

Swatch before you order the lot

Matching metres only works if your stitches come out the same size. Buy one ball of the new yarn, crochet a tension square in the pattern’s stitch with the pattern’s hook, and compare it with the tension the designer gives. If your square is bigger, the project will use more yarn than the metres sum suggests. If it’s smaller, change hook before you change the quantity.

Once the tension matches, do the metres sum, round up, and order the full amount from one dye lot if the shop lets you choose.

Common questions

Sources and scope

• www.stylecraft-yarns.co.uk/yarns/special-dk/
• www.stylecraft-yarns.co.uk/yarns/life-dk/
• www.stylecraft-yarns.co.uk/yarns/naturals-bamboo-cotton/
• www.paintboxyarns.com/yarns/simply-dk/
• www.paintboxyarns.com/yarns/cotton-dk-50g/
• sirdar.com/en/products/hayfield-bonus-dk-100g
• sirdar.com/en/products/sirdar-snuggly-dk-50g
• www.kingcole.com/product/big-value-dk/
• www.kingcole.com/product/cottonsoft-dk/
• www.kingcole.com/product/merino-blend-dk/
• www.scheepjes.com/en/colour-crafter-328/
• wyspinners.com/products/colourlab-dk-yarn
• www.rico-design.com/rico-baby-classic-dk-50g-165m
• www.rico-design.com/essentials-merino-dk-50g-110m
• www.woolwarehouse.co.uk/yarn/drops-merino-extra-fine-all-colours
• www.woolwarehouse.co.uk/yarn/drops-lima-all-colours
• www.woolwarehouse.co.uk/yarn/drops-cotton-light-all-colours
• hobbii.co.uk/collections/baby-yarn/products/hp-1001671-rainbow-cotton-8-8
• www.craftyarncouncil.com/standards/yarn-weight-system

Sources checked 1 October 2026. Label facts come from the linked references; worked purchase examples and arithmetic are our own illustrations.