How to Choose Yarn for Knitting and Crochet Projects
Match the yarn to your pattern before you match it to your budget. The pattern's gauge, the fiber's behavior, and the total yardage you need decide whether the finished piece fits and wears well — price per ball only matters after those three are settled. The steps below work for any project; the product examples come from NuMei's yarn catalog, where free shipping applies within the contiguous USA on orders over US$100.
Start with yarn weight, not color
Yarn weight is the single biggest factor in whether your finished size comes out right. A pattern written for worsted yarn will not produce the same measurements if you substitute bulky, even with the same stitch count.
| Weight | Typical use | Watch for |
|---|---|---|
| Lace / fingering | Socks, shawls, fine garments | Long yardage per ball, slow progress |
| Sport / DK | Light sweaters, baby items | Gauge sits between fingering and worsted |
| Worsted | Sweaters, hats, blankets | The most common pattern weight |
| Bulky | Quick hats, thick blankets | Fewer yards per ball than you expect |
Check the recommended needle or hook size on the label and compare it to the size your pattern calls for. If they differ by more than one step, the yarn is probably the wrong weight for that pattern.
Pick fiber by how the item will be used
Fiber decides warmth, drape, stitch definition, and how the item survives washing.
- Wool — warmth and memory (it springs back into shape). Good for sweaters, mittens, and anything that needs to hold structure. Sock yarns like Berlini Merino Velvet Sock combine wool with nylon for durability.
- Cotton — breathable with excellent stitch definition. Suits summer tops, bags, and washcloths. Less elastic than wool, so it can stretch under its own weight. Berlini Cotton Lumi is a 50g cotton ball at $4.49, or $3.79 on sale.
- Acrylic and blends — easy care and budget-friendly. A practical choice for baby items and blankets that get washed often.
- Fur and novelty yarns — texture rather than stitch definition. YarnArt Fable Fur (100g, $5.99) is built for trim and fluffy accents, not for structured garments.
If the pattern names a fiber, substituting changes the fabric. A cotton version of a wool sweater will hang differently and may grow longer with wear.
Read the label before you commit
Every ball carries the information you need to plan quantity:
- Ball weight and yardage — 50g and 100g balls are common here, but yardage varies widely by fiber and weight. Two 100g balls of different yarns can differ by hundreds of yards.
- Recommended needle or hook size — your starting point for swatching.
- Dye lot — the batch number for that color. Balls from different dye lots can look identical in the store and visibly different once knitted side by side.
Calculate how many balls you need
Work from the pattern's total yardage, not from the number of balls another knitter used.
- Find the total yardage the pattern requires for your size.
- Divide by the yardage printed on one ball of your chosen yarn.
- Round up to the next whole ball.
- Add one extra ball.
The extra ball covers gauge differences, a longer body or sleeve, and mistakes. It also protects you if the dye lot sells out — running short mid-project with a discontinued dye lot is the most common way a project stalls.
Compare price per yard, not price per ball
A $2.99 ball and a $5.99 ball are not comparable until you know the yardage in each. Divide the price by the yards to get cost per yard, then compare.
Bulk buying changes the math. Several yarns in this catalog are priced both per ball and per bag:
| Yarn | Per ball | Bag price | Saving |
|---|---|---|---|
| Berlini Cotton Lumi 2015 Ivory (50g) | $4.49 → $3.79 | Bag of 10: $29.90 | $0.70 off the ball price |
| Tropical Lane Pregiata 334 Carnation (50g) | $3.99 | Bag of 10: $27.50 → $19.90 | $7.60 off the bag |
| Filtes King Riviera 4 Fiery Red (50g) | $3.99 | Bag of 10: $29.90 → $27.50 | $2.40 off the bag |
| Berlini Merino Velvet Sock 106 Aegean Sea (50g) | $6.99 → $4.99 | Bag of 10: $44.90 → $39.90 | $5.00 off the bag |
| Berlini Merino Velvet Worsted 101 Woodland Camouflage (100g) | $12.99 | Bag of 5: $46.50 | — |
| Berlini Memento Royale 153 Bon Bon (50g) | $8.99 | Bag of 10: $52.50 | — |
A bag only saves money if the quantity matches your project. Ten balls of sock yarn is roughly two to three pairs of adult socks — useful if you knit socks regularly, wasteful if you need one. Buy the bag when your calculated ball count is close to the bag size and you will use the leftovers; otherwise buy singles.
Buy all skeins in one dye lot
Order every ball your project needs in a single purchase. Balls shipped together from the same listing are far more likely to share a dye lot than balls bought weeks apart. If you must buy later, check the dye lot number on arrival and compare it to your existing balls before knitting them in — alternating balls every few rows can blend a slight mismatch, but it cannot fix a clearly different shade.
Quick decision path
- Following a pattern exactly? Buy the weight and fiber it specifies, in the total yardage it lists, plus one ball.
- Substituting yarn? Match the weight first, then choose a fiber with similar behavior, then recalculate ball count from the new yardage.
- Budget-limited? Compare cost per yard across weights, and check whether a bag price beats singles for the quantity you actually need.
- Gift or baby item? Prioritize easy-care fiber over luxury fiber.
- One-off small project? Buy singles; a bag discount is not a saving if the rest sits unused.
If your order reaches US$100 within the contiguous USA, shipping is free — worth factoring in when deciding between singles and a bag.