Yarn Weight Conversion Guide — When Your Pattern Calls for a Discontinued Yarn

You've found the perfect pattern and tracked down the specified yarn — only to discover it was discontinued three years ago. Or the yarn exists but you can't find it in your country, or it's far outside your budget. This happens constantly, and it's completely solvable. Yarn substitution is a skill worth developing, and once you understand what actually matters in a substitution, you'll be confident doing it for any project.

Step 1: Identify the Original Yarn's Key Properties

Before you look for alternatives, you need to know exactly what you're trying to match. Pull up the original yarn's listing (Ravelry keeps records of discontinued yarns, as do most yarn databases) and note four things:

Weight category: The CYC number (0–7) or the word label (lace, fingering, DK, worsted, etc.)

Stated gauge: The manufacturer's recommended gauge in stitches per 4 inches / 10cm — this is more precise than the weight category

Fibre content: The specific fibres and their percentages, in order

Meterage per weight: How many metres per 100g (or yards per skein)

Of these, gauge is the most important single number. The weight category is a coarse label — two yarns both labelled "DK" can have meaningfully different gauges, which will affect your finished fabric. Gauge is what your needles actually measure.

Step 2: Find the Pattern's Actual Gauge Requirements

The pattern will specify a gauge swatch — for example, "22 sts and 30 rows = 4 inches / 10cm in stockinette on 4.5mm needles." This is the gauge you need to match, not just the yarn's label weight. Sometimes patterns are worked at a gauge that differs from the yarn's default — a designer might use a heavier yarn on smaller needles for a denser fabric, or a finer yarn on larger needles for drape.

Your substitute yarn needs to be able to achieve this gauge. If you're substituting a lighter yarn, you'll need smaller needles; if heavier, larger needles. But there are limits — you can't ask a sock-weight yarn to work as a DK-weight no matter what needles you use, because the fabric will be too stiff or the stitch definition will be wrong.

As a rule of thumb: aim for a substitute within one weight category of the original, preferably the same weight category.

Step 3: Consider Fibre Content and Why It Matters

Fibre content affects drape, stretch, durability, warmth, sheen, and hand feel — all of which can change how a finished garment wears and fits. Here's what matters most:

Wool (non-superwash): Has memory, will felt if agitated wet, grows when blocked. If the original yarn was non-superwash wool and you substitute with a yarn that felts differently, your gauge after wet blocking may be very different.

Superwash wool: Machine washable, slightly more stretchy and drapey than regular wool, tends to grow more when wet blocked. Substituting superwash for non-superwash wool can result in a larger finished garment — factor this in, especially for socks and fitted garments.

Plant fibres (cotton, linen, bamboo): No memory, heavy, very drapey. Substituting a wool pattern with a plant fibre yarn will produce a different-feeling garment — potentially more drapey and heavier. Garments designed for plant fibres don't translate well to wool, and vice versa.

Synthetic fibres (acrylic, nylon): Very stable, no blocking, can feel plastic depending on quality. High-quality acrylic can substitute for wool in terms of gauge behaviour, but the finish and drape will differ.

Blends: Most sock yarn is wool/nylon blend (80/20 or 75/25). This blend is the most common substitution target in socks. Any sock yarn at the right gauge in a wool/nylon blend will behave similarly.

Step 4: The Twist Test

Twist — how tightly the fibres are plied together — affects stitch definition, durability, and how the yarn knits up. A very tightly twisted 2-ply yarn will behave differently from a loosely spun single of the same weight and gauge.

Look at both yarns in a good light and compare: do they have a similar ply structure? Are they similarly tightly twisted? A tightly plied substitute for a loosely spun original will give you crisper stitch definition (which can be good or bad depending on the project). A loosely spun substitute for a tightly plied original will give you a halo and less stitch definition.

For cables and textured stitches, you want a tightly plied yarn — it makes the stitch definition pop. For colourwork, you want a smooth, consistent yarn with minimal halo. For plain stockinette, twist matters less.

Step 5: Calculate Meterage and Adjust Your Quantity

Once you've identified a substitute, work out how much you need. The pattern will specify total yardage or meterage — use this, not the number of skeins. If the original yarn had 200m per 100g and your substitute has 230m per 100g, you need fewer grams of the substitute to reach the same meterage.

Always buy one extra skein as insurance. Dye lots will vary between purchases, and running out is far more annoying than having a leftover skein you can use for swatch samples or future repairs.

Step 6: Swatch, Block, and Remeasure

This step is not optional. Cast on at least 30 stitches and work 30+ rows in the stitch pattern the project uses (not just plain stockinette — if the pattern uses cables, swatch in cables). Wash the swatch exactly as you intend to wash the finished item. Block it the same way. Let it dry completely, then measure.

If your swatch gauge matches the pattern gauge, you're ready to start. If it doesn't, adjust needle size and re-swatch before starting the project. A garment knitted at the wrong gauge will not fit — checking on a swatch takes an afternoon; re-knitting a sweater takes months.

Where to Find Yarn Substitutes

Ravelry Yarn Substitutions: Many pattern pages on Ravelry have a "Yarn Substitutions" tab where other knitters have documented what they used instead of the original yarn.

LoveCrafts and Wool Warehouse: Both have yarn browsing by weight and fibre, making it easy to narrow down options.

Your local yarn shop: Ask the staff — they're often very good at substitution recommendations and can let you handle the yarn in person before buying.

The yarn brand's website: Some brands publish substitution guides for their own discontinued yarns.

Not sure if your substitute will work? Emma can help you check before you buy →