You found the perfect pattern. The design is right, the size fits, you can already imagine it on your body. Then you read the Yarn Recommendation – and the suggested yarn is no longer available, not in your budget, or you simply have another one in mind that you absolutely want to knit.

Welcome to the world of Yarn Substitution. It’s one of the most common situations in Knitting – and at the same time one of the places where most mistakes happen. Not because it’s complicated, but because often the wrong things are compared.

This article shows you step by step how to safely swap one yarn for another, what really matters, and where the typical pitfalls lie. With concrete examples from the BONIFAKTUR Assortment, so you can put theory directly into practice.

Why substitute at all?

There are many good reasons to use a different yarn than the one specified in the pattern:

The recommended yarn is no longer available – yarns get discontinued, brands disappear, color lines change. You prefer a different fiber – maybe you want a non-Superwash yarn instead of Superwash, or a Cotton blend for summer instead of pure Wool. You already have yarn in your stash that you finally want to knit up. Or you simply fell in love with another yarn and want to use it for this exact project.

All of this is completely legitimate. Designers recommend a specific yarn because they developed and tested the pattern with it – not because it’s the only possible yarn for the pattern. The art lies in finding a substitute that behaves similarly enough so the result is right.

The four key factors

When you substitute a yarn, there are four properties you need to compare. They are not all equally important – but all relevant.

1. Yarn Weight

Yarn Weight is the most important factor. It determines how thick the yarn looks on the needle and how many stitches you knit over 10 cm. Swapping one Fingering yarn for another Fingering yarn is usually straightforward. Swapping a Fingering yarn for a DK yarn fundamentally changes the entire project – size, Drape, yarn consumption, everything.

As a rule of thumb: Staying within the same Yarn Weight category is the safest starting point. But Yarn Weight categories are not fixed boxes – they overlap, and two yarns in the same category can still feel quite different on the needle. Ultimately, the Gauge matters more than the label. If you switch a category up or down (for example from DK to Worsted), you need to adjust needle size, stitch count, and yarn amount – this is possible but significantly more work.

If you’re unsure about the Yarn Weight categories and what they mean: Our Yarn Weight article explains everything from Lace to Bulky.

2. Meterage per 100 g

Within a Yarn Weight category, there are significant variations. Two yarns can both be considered "Fingering" and still have very different meterages. KFO Merino has 500 m/100 g, Hedgehog Fibres Sock Yarn comes in at 400 m/100 g – both Fingering, but the meterage tells you that the Hedgehog is a bit thicker.

Meterage is a very useful comparison value, especially together with Gauge, Fiber, and Construction. The closer the meterages are, the more likely you are to knit a similar result – but two yarns with identical meterage can still behave differently if fiber, twist, or construction differ.

Important: The Meterage also depends on the Material. Plant Fibers like Linen and Cotton are heavier than Wool – a linen yarn like BC Garn Lino has "only" 300 m/100 g but still behaves like a Fingering yarn on the needle. Because fibers vary so much in density, it is most meaningful to compare Meterage within the same fiber group – Wool with Wool, Cotton with Cotton. Across material groups, Needle Size and Gauge are more helpful than just the meter count.

3. Fiber and Fiber Composition

This is where it gets exciting – and where most unexpected surprises happen. Two yarns can have exactly the same Yarn Weight and Meterage and still behave completely differently because the fiber is different.

Wool has elasticity (crimp) and memory – the fabric springs back and holds its shape. Cotton has little elasticity and gets heavier the more you knit – a sweater made of cotton stretches out over time, one made of wool does not. Linen is stiff and only softens with each wash. Silk has sheen and drape, but no memory. Alpaca is soft and warm, but stretches out easily like cotton.

If the pattern recommends a Merino yarn and you substitute with Cotton, you will get a fundamentally different result – even with the same gauge. The fabric becomes heavier, less elastic, and has a different drape. This can be intentional, but you should decide consciously.

Superwash vs. Non-Superwash is another critical point. Non-Superwash wool (like all KFO yarns) is prone to felting and shrinking from heat, friction, and machine wash. Many Non-Superwash yarns develop a bloom after the first wash – the stitch definition becomes fuller and softer – with the extent and type of bloom varying depending on fiber, spinning method, and finishing. Superwash yarns (like Malabrigo Rios) are machine washable and generally show less bloom. If the pattern is designed for Superwash and you substitute with Non-Superwash, you need to adjust care. Our Superwash article explains the differences in detail.

4. Yarn Construction (Ply)

A often overlooked factor: How is the yarn constructed? A Single Ply behaves differently than a 4-ply (four twisted strands). Singles often have more drape and show colors especially vividly, but tend to be less shape-retentive and more prone to pilling and abrasion. Multi-ply yarns are generally more durable, hold their shape better, and show clearer stitch definition – ideal for cables and textured patterns.

If the pattern recommends a plied yarn and your design relies on cables or texture, a single ply is probably not a good choice – the patterns get lost in the softer stitch definition. Conversely, a stiff 4-ply is not ideal if the design depends on flowing drape.

More on this in our Single Ply vs. Multi Ply article.

Step by step: Here’s how to proceed

Step 1: Analyze the pattern

Note the details of the recommended yarn: Yarn Weight, meterage per 100 g, fiber, recommended needle size, and the specified gauge. These five values are your reference frame.

Step 2: Find substitute yarn

Look for a yarn that shares as many of these values as possible. The priority order:

First, the gauge – if you reach the specified gauge, you’re on the right track, no matter the yarn name. Second, the yarn weight – stay in the same category. Third, the meterage – the closer, the better. Fourth, the fiber – the same fiber group ensures similar behavior. Fifth, the yarn construction – the same ply structure for pattern-intensive designs.

Step 3: Calculate yarn quantity

Always calculate in meters, not balls. If the pattern recommends 1200 m, you need 1200 m – whether that’s 12 balls of 100 m or 5 balls of 250 m.

Note: If your substitute yarn has a slightly different meterage and you use a different needle size as a result, the total consumption may change. A yarn you knit on larger needles tends to need slightly fewer meters (but not always – the gauge decides).

Step 4: Knit a gauge swatch

The most important step. Knit a generous gauge swatch of at least 15 × 15 cm with your substitute yarn and the recommended needle size. Wash and block the swatch as you would treat the finished piece. Only then measure.

Is the gauge correct? Perfect. Is it off? Try a different needle size. If after two or three attempts you still don’t reach the pattern’s gauge, the yarn might not be a good substitute for this particular project.

The Gauge is even more important for substitutions – it is your only objective test to see if the swap works.

Concrete examples from the assortment

Theory is good, practice is better. Here are some typical substitution scenarios with yarns you can find at BONIFAKTUR.

Swap Fingering Merino

The pattern recommends a standard Fingering Merino. Possible alternatives:

KFO Merino (500 m/100 g, non-superwash) and Madelinetosh Tosh Merino Light (359 m/100 g, superwash) are both Fingering Merinos but with clear differences: KFO Merino is finer and non-superwash, Tosh Merino Light is a bit thicker and superwash with hand-dyed color character. Both can work in the same pattern – but you’ll likely need different Needle Sizes and get a noticeably different fabric. KFO Merino produces a finer, matte Stitch Definition with Bloom after washing; Tosh Merino Light brings livelier colors and more substance.

Worsted versus Worsted

KFO Heavy Merino (250 m/100 g, non-superwash) and Malabrigo Rios (192 m/100 g, superwash) are both classified as Worsted – but the clearly different meterage shows they are not simply interchangeable. Rios is noticeably thicker and heavier per meter, and also superwash. This means: more balls for the same project and different behavior when washing. For a Sweater that needs regular Machine Wash, Rios is the more practical choice. For a shawl that is rarely washed and needs maximum softness, KFO Heavy Merino has the edge.

Fiber swap: Wool versus blend

If a pattern recommends a pure Merino Fingering and you want to use Holst Garn Coast (55% Merino, 45% Cotton, 700 m/100 g) instead, a lot changes. Coast is finer than a standard Fingering (more like Light Fingering), has less Elasticity due to the Cotton content, and a cooler Hand Feel. This can be great for a summer shawl or a light accessory – but less so for an elastic ribbed Sweater. Here, the Gauge helps, but also an honest look at the intended use.

DK range: Not all DKs are the same

Sandnes Peer Gynt (182 m/100 g, 100% Norwegian Wool, DK) is the classic Stranded Colorwork yarn – sturdy, shape-retaining, with clear Stitch Definition. If the pattern recommends a soft DK Merino and you use Peer Gynt, you’ll get a more rustic, firmer result. Perfect for Colorwork and Stranded Colorwork; not the best choice for a soft baby Sweater. The Yarn Weight matches, but the character of the yarn is different.

The most common mistakes in substitution

Only look at the Yarn Weight. “Both are Fingering” is not enough – always compare meterage, fiber, and construction as well.

Skipping the gauge swatch. Especially when changing yarn, the swatch is indispensable. Two “identical” yarns can produce completely different gauges on the same needle size.

Ignoring Superwash differences. Many Non-Superwash yarns noticeably change after the first wash – the stitch definition can become fuller and softer. If you measure your gauge swatch unwashed and use a Non-Superwash yarn, the values will likely be different after washing. Always measure the washed and blocked swatch.

Calculating yarn amount in balls instead of meters. “The pattern says 8 balls” is useless if your substitute yarn has different ball sizes. Always calculate in total meters and plan 10–15% extra.

Forgetting the intended use. A soft Single Merino can give a wonderful gauge swatch, but for socks it would be a disaster – not stable enough, no Nylon for abrasion resistance. The gauge tells you if the measurements are right, not if the yarn suits the project.

When You Shouldn’t Substitute

There are situations where swapping yarn is risky:

For very structured designs (Cables, complex textures), where the designer has specifically chosen the yarn for its properties. For projects with very little tolerance – a snug sock or a precisely tailored garment with darts forgives deviations less than a loosely flowing shawl. And if you just can’t match the gauge: then this yarn isn’t right for this project. No drama – there’s always another pattern that fits perfectly.

Conclusion

Yarn substitution isn’t rocket science, but it’s not guesswork either. With the four key factors – Yarn Weight, Meterage, Fiber, and Yarn Construction – and an honest gauge swatch, you’ll reach your goal safely.

The great thing about it: Changing yarn is also an opportunity. Your substitute yarn brings its own character – different colors, a different hand feel, a different light. The result won’t be identical to the original design, but it will be yours. And often enough, it will even be better because you chose the yarn that truly excites you.

Knit a swatch. Trust your hands. And then: go.

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