Tension (or Gauge) is the number of stitches and rows measured usually in a 4"/10cm square. You gauge is effected by:

• The stitch 
• The hook
• The yarn
• Your personal style

Tension isn't crucial for every pattern, but it will effect everything you make.  For items like crocheted flowers, a looser tension will mean a bigger flower, but for a cardigan, it will mean one that may not fit the intended recipient.

Controlling Your Tension

Quite often, I will see comments about people "trying to work tighter/looser to get gauge".  While, yes, if you crochet extremely tightly or extremely loosely, then working on your technique is a good idea.  But if you are going to be working on a pattern that really needs to fit - it is a much better idea to change your hook size.

The diameter of your hook controls the amount of yarn taken into you stitch.  A bigger hook takes in more yarn , making the stitches bigger.  A smaller hook takes in less yarn, making the stitches smaller.

Remember that your gauge can change.  While I am a loose crocheter and knitter at the best of times, pregnancy and hand fatigue both make my gauge MUCH looser.  If I am working on large projects, I often need to change hooks half way through.

Making a Swatch

At the beginning of the pattern, you will see a line of instruction that reads something like:

This tells you that using the suggested hook and stitch, you measure the number of stitches and rows specified in a 4"/10cm square. (note: some designers will use a different measurement for their square, 2" is a common alternative)

The most straight forward way of making a swatch is to work a square using the number of stitches and rows in the tension guide. However, you may need to adjust for any half measurements or special stitches indicated. 

For garments or items where fit is going to be crucial, make a swatch bigger than just 4" square  to ensure tension is right across the garment.

Things to note:

- If you make your swatch  and it is smaller than 4"/10cm square (ie you need MORE stitches and rows make up 4" than the tension guide), then you need to use a bigger hook.

- If you make your swatch and it is larger than 4"/10cm square (ie you need fewer stitches and rows make up 4" than the tension guide), then you need to use a smaller hook.

- If only your stitches OR your rows match the gauge, then you may need to think about changing the yarn you are using.

- If your item is only very small (perhaps a hat, a baby's cardigan, a set of gloves), it is not unthinkable to actually start the pattern if you can measure your gauge from the first  portion. Treat it as any swatch, with a wash and a block, but then continue on from there once it is dry.

- Make sure you wash and block your swatch as you plan on doing with your finished item. That is the only way you can be certain that your finished project will be the size you need it to be at the end of the day. If you have to change hook or yarn, repeat the process of washing.

More about Tension/Gauge:

- the tension of your crochet effects the drape of your project