Tension is the knitter’s best friend but is often the part of a project that knitters like the least. Mention swatching to most knitters and wait for the sighs! Nevertheless, as tempting as it may be to dive right in, checking your tension, even when you are using precisely the same yarn as that specified in the pattern, really is essential. Every knitter's tension is unique - and there's nothing wrong with that!

What is Tension in Knitting?

Tension (referred to as gauge in US patterns) is the size (length x width) of a knitting stitch worked on a specific size of needle in a given yarn using a specified technique. If you knit more loosely or more tightly than the designer your garment may not be the same size as the one the designer knitted. Your knitting is not ‘wrong’, it is simply that we all knit slightly differently and your tension is not identical to the designer’s.

Your knitting is not ‘wrong’, it is simply that we all knit slightly differently

What Difference does Tension Really Make?

But does it really matter? Yes! If your stitches are just an eighth bigger than the designer’s, for every 100 stitches the designer casts on, your work will measure the equivalent of 12 stitches larger. On a shawl with 400 stitches, that’s the equivalent of an extra 50 stitches without you having cast on a single extra stitch. Equally, if your tension square is smaller than the designer’s, your garment will be correspondingly smaller.

Here's the good news: this problem has the easiest fix in the world - just find the right needle size for you!

How to Knit a Tension Swatch

Check the stated stitch, needle size and measurements recommended to achieve the correct size for your garment. Usually this information is at start of pattern. Start with the recommended needle size, unles you know your tension is always super-loose or super-tight, in which case you might want to go down or up a size.

In this example, we'll be starting with 4mm needles.

Cast on about one and a half times the number of sitches stated in the tension notes in the pattern, plus 10. In this case, I would cast on 43 sts. This allows for variations in edge stitches and gives an undistorted central section to measure from.

You should always work your tension swatch in the same stitch as listed in the pattern. In this example it's stocking stitch but you may need to check your tension using a lace, cable or colourwork pattern. It's important to swatch in the stated pattern because your tension may vary between different stitch techniques.

If your tension is not measured in stocking stitch, we recommend working 6 rows of garter stitch (knit every row) before you begin working in the pattern, and work the first 5 and last 5 sts of each row in garter stitch as well, to give a clear border to your swatch.

On your first pattern row (this will be a knit row if your swatch is in stocking stitch), lay a piece of smooth, contrasting waste yarn (approximately 30cm long) between needles 5 sts before end of row. Keep three quarters of waste yarn to front, one quarter to back.

At the end of your 4th (knit) row, flip the waste yarn from knit (RS) to purl (WS). This will form a ‘running stitch’ vertically along edge where we will measure your swatch. This will speed up measuring later.

Top Tip!

If a pattern is to be knitted in the round, make sure you knit your swatch in the round. Tension is often different when comparing circular to flat knitting!

On the following (purl) row, flip the waste yarn, taking it between the needles from purl (WS) to knit (RS). Repeating steps 3-4 throughout, work 2-4cm in stocking stitch, ending with a purl row.

Work next knit row, then insert a lifeline by threading a length of contrasting, smooth waste yarn through the sitches which are currently on the needle. This gives a clear line from which to measure your swatch. Take care not to split this thread when working your next row.

Top Tip!

If you change needles to achieve tension, remember to adjust all needles (for example, needles for ribs or bands) correspondingly

Continue to work your swatch exactly as stated in the pattern (remembering to allow for extra edge stitches and flipping yarn for marking the edge) until your work measures approximately 15cm from your lifeline. Then work a further 2-4cm in stocking stitch (if you're working a stocking stitch swatch) or 6 rows in garter stitch (if you're working a patterned swatch).

Cast off, block and finish swatch.

It is very important to wash, block and finish your swatch in exactly the same manner as you will wash, block and finish your garment. For example, if you're going to wash your jumper the the washing machine - throw you swatch in that washer! Many yarns can either grow or shrink when they're washed and blocked, and you don't want this catching you out.

Using a ruler, in the centre of your swatch, measure and place a pin horizontally at the length stated in your pattern (usually 10cm). Measure from just above lifeline. Count the number of rows between the lifeline and pin. Include half, quarter or partial rows.

In stocking st, each row looks like a series of ‘v’ shapes. Two rows are shown here, marked between the pins.

Top Tip!

When substituting yarn, consider not only tension but also drape, appearance and handle. Use stated yarn as a guide and check ballbands for yarn with similar tension.

Use a ruler to measure stated width (usually 10cm). Measure across the centre of your swatch, starting from LH running stitch line. Mark the stated pattern measurement by inserting a long pin vertically through your work. Count the stitches between running st and pin. Include any half, quarter or partial stitches.

Shown between pins are two stitches. Each ‘v’ represents a single stitch.
If your finished measurements match the pattern, proceed knitting with the needles you have been using.
If your square is too small, repeat this swatching exercise using a larger needle size.
If your square is too large, try again with smaller needles.

Top Tip!

Keep swatches for future reference in a folder or box (carefully labelled!) as these may come in handy if you knit the project or use the same yarn again.

About Debbie Tomkies

Debbie is Knit Now's resident expert knitter, and she's been writing for us since Issue 1. She's a talented textile designer, author and teacher. What she doesn't know about yarn isn't worth knowing! You can find all about her at debbietomkies.co.uk

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