Yarn for knitting comes in a great many varieties. Which you choose depends on your pattern, your experience and your budget.
It can be made from wool, mohair, cashmere, alpaca, angora, silk, cotton, linen, acrylic, or any combination of those. For most easy projects I would suggest a simple acrylic: inexpensive and forgiving, which are the two things a beginner most needs.
Once you have chosen a material, the next decision is weight.
What weight means
Weight is the thickness of the yarn, not how much a ball weighs. It determines how many stitches you get to the inch, which determines how long a project takes and what the finished fabric is like.
It is the single most important number when substituting one yarn for another. Fibre affects how a fabric behaves; weight affects whether it comes out the right size at all.
The weights, roughly
Lace. The finest. Shawls and delicate accessories. Beautiful and slow.
Fingering / sock. Socks, fine shawls, lightweight garments. Hard-wearing when blended with nylon.
Sport / DK. A good middle ground – baby garments, light sweaters, accessories. Fine enough to look neat, thick enough to progress.
Worsted / aran. The most common weight and the best place to start. Sweaters, hats, blankets, scarves. Most patterns are written for it and most yarn is sold in it.
Bulky and super bulky. Very fast. Chunky hats, heavy scarves, quick blankets. Also rug yarn and similar heavy applications.
What to choose for a first project
Worsted weight. It is thick enough that stitches are easy to see and the work grows visibly, and thin enough that the finished fabric is not stiff and unwieldy.
Bulky is tempting because it is fast, but chunky fabric is harder to work neatly and mistakes are more visible. Anything finer than sport weight is simply slow, and slow progress is discouraging early on.
Colour and texture matter for a beginner
Choose a light, solid colour in a smooth yarn.
This is not aesthetics. Dark yarn makes it genuinely difficult to see individual stitches, and fuzzy or variegated yarn hides the stitch structure. Being unable to see what your hands have done is the most common reason people conclude they cannot knit.
Substituting
Match the weight first, then the fibre, then compare yardage rather than ball weight – two 100g balls can hold very different lengths.
Then swatch. The ball band’s stated gauge is what the manufacturer got, not what you will get.
