Hobbii Rainbow Cotton 8/4 vs Katia Fair Cotton

Technical verdict: Hobbii Rainbow Cotton 8/4 vs Katia Fair Cotton

Weight category, yardage and value per ball

Hobbii Rainbow Cotton 8/4 and Katia Fair Cotton are both Fine (CYC 2) yarns, so on paper they are interchangeable in the same patterns. The weight class only tells half the story, though: the ball band data below shows how much they really differ in thickness, yardage and behaviour once they are on the hook.

Hobbii Rainbow Cotton 8/4 is the longer yarn per gram, with 340 m per 100 g against 310 m per 100 g for Katia Fair Cotton, a difference of 10 %. For the same 1,000 m of yarn, the project weighs about 294 g in Hobbii Rainbow Cotton 8/4 and 323 g in Katia Fair Cotton. A lower m/100 g figure means a thicker or denser strand, so the heavier yarn will also make a slightly thicker, warmer fabric.

Per ball, Hobbii Rainbow Cotton 8/4 holds 170 m in 50 g and Katia Fair Cotton holds 155 m in 50 g. Five balls of Hobbii Rainbow Cotton 8/4 (850 m) are replaced by 6 balls of Katia Fair Cotton, and five balls of Katia Fair Cotton (775 m) by 5 balls of Hobbii Rainbow Cotton 8/4. Always convert by length, never by weight or by number of balls.

Drape, fibre and texture

Both yarns share the same fibre family: Hobbii Rainbow Cotton 8/4 is 100 % cotton and Katia Fair Cotton is 100 % cotton, so they wash, block and wear in a similar way. Cotton is inelastic and absorbent: stitches look crisp and defined, the fabric holds its shape in amigurumi, bags and dishcloths, but garments can feel heavy and stretch downwards when wet.

Within the same weight class, Hobbii Rainbow Cotton 8/4 has noticeably more meters per gram, so its fabric will be lighter and drape more softly, while Katia Fair Cotton will feel denser and more structured. Choose the lighter one for shawls, tops and baby items, and the denser one for bags, amigurumi and pieces that must hold their shape.

They also share the same construction (Plied), so stitch definition and the way the yarn behaves on the hook should feel familiar when you switch.

Hook size and gauge

The ball bands recommend 2.5–3 mm for Hobbii Rainbow Cotton 8/4 and 3 mm for Katia Fair Cotton. The ranges overlap at 3 mm, which is the safest hook to start a test swatch for either yarn.

At least one manufacturer does not publish a reference gauge, so work a 12 × 12 cm swatch with your usual hook before comparing sizes.

Verdict: can you swap them?

Katia Fair Cotton is a strong substitute for Hobbii Rainbow Cotton 8/4, with a Match Score of 81 %. Convert by length with the calculator above, work a quick swatch, and most patterns will need no other changes.

Hobbii Rainbow Cotton 8/4 gives more meters per ball, so you will usually buy fewer balls. Hobbii Rainbow Cotton 8/4 makes the lighter fabric; Katia Fair Cotton makes the denser one.

Whichever you choose, buy all the balls for a project from the same dye lot and keep the ball band for its care instructions.

Full Hobbii Rainbow Cotton 8/4 data sheet → Full Katia Fair Cotton data sheet → Calculate yarn for a whole project →