How to Knit and Measure a Gauge Swatch (and Fix Gauge That's Off)
Knit a swatch, block it and count stitches and rows in 10 cm. What to do when your gauge doesn't match the pattern, with the maths to adjust stitch counts.
The short answer: knit a square at least 15 cm wide in the pattern’s stitch, wash and dry it like the finished piece, then count the stitches and rows across 10 cm in the middle. Too many stitches: go up a needle size. Too few: go down. Or keep your gauge and let the gauge calculator recalculate the stitch counts.
Gauge (called tension in British patterns) is the number of stitches and rows in 10 cm, or 4 inches, of knitted fabric. Every stitch count in a pattern depends on it. A pattern that says “cast on 220 stitches” for a 100 cm chest assumes you get 22 stitches in 10 cm. If you get 20, the same 220 stitches measure 110 cm; if you get 24, they measure about 92 cm.
That is why the swatch matters more than the needle size in the pattern.
How to knit a gauge swatch
- Use the pattern’s yarn and needles. Start with the needle size in the pattern, or the middle of the range for your yarn weight.
- Cast on enough stitches for 15 cm or more. Take the pattern’s gauge, add half again, and add a few stitches for edges. For a gauge of 22 stitches per 10 cm, cast on about 36.
- Knit in the pattern’s stitch. If the pattern gives gauge “in stockinette”, knit stockinette. If it gives gauge in the cable or colourwork pattern, swatch that pattern. A few garter stitches at each edge stop the swatch from curling.
- Work 15 cm or more.
- Knit it the way you will knit the garment. If the sweater is knit in the round, knit the swatch in the round too (or use the “speed swatch” method: work every row from the right side and let the yarn float loosely across the back). Many knitters purl more loosely than they knit, which changes gauge between flat and circular fabric.
- Bind off loosely and wash it. Wash and dry it exactly as you will treat the finished piece. Let it dry flat without stretching.
How to measure gauge
- Lay the swatch flat on a table without stretching it.
- Place a ruler or gauge tool in the middle, away from the edges.
- Stitches: count the knit Vs across 10 cm along one row. Count half stitches; they matter.
- Rows: count the Vs vertically across 10 cm in one column.
- Measure in two or three places and take the average.
If 10 cm is hard to count, measure across more stitches and work it out: 33 stitches over 15 cm is 33 ÷ 15 × 10 = 22 stitches per 10 cm.
When your gauge doesn’t match
| Your swatch | Meaning | What to do |
|---|---|---|
| More stitches than the pattern | Your stitches are smaller | Go up a needle size |
| Fewer stitches than the pattern | Your stitches are larger | Go down a needle size |
| Stitches match, rows don’t | Common, especially flat vs round | Keep the needle; follow lengths in cm, not row counts |
Change one size at a time, swatch again, and repeat until the stitch count matches. For converting between US, UK and metric needle sizes, see the needle size chart.
Keep your gauge, change the numbers
Sometimes you want the fabric you have: the yarn looks right at your gauge, or you are working without a pattern. Then recalculate the counts instead of changing needles.
Stitches to cast on = width you want (cm) ÷ 10 × your stitches per 10 cm
Rows to knit = length you want (cm) ÷ 10 × your rows per 10 cm
Example: you want a 50 cm wide blanket and your swatch gives 18 stitches per 10 cm. 50 ÷ 10 × 18 = 90 stitches.
The Knytstudio gauge calculator does this in both directions: from centimetres to stitches, and from a pattern’s stitch count to the size it will come out at your gauge.
Gauge in colourwork and charts
Stranded colourwork usually knits tighter than plain stockinette, because the carried yarn pulls the fabric in. Swatch in the colourwork pattern if the garment has a colourwork section, and use a larger needle there if needed.
Knitted stitches are also not square: at a typical gauge of 22 stitches and 30 rows per 10 cm, each stitch is wider than it is tall. A motif drawn on square graph paper comes out squashed vertically when knitted. When you chart a motif in Knytstudio, the chart knows your gauge and gives the finished size in centimetres, plus written row-by-row instructions and a check for long floats.
Frequently asked questions
How big should a gauge swatch be?
At least 15 x 15 cm (6 x 6 in), so you can measure 10 cm in the middle away from the edges. Bigger swatches give a more accurate count, especially in textured or colourwork patterns.
Do I need to wash my gauge swatch?
Yes. Wash and dry it the way you will treat the finished piece. Many yarns grow or shrink when wet, and the gauge after blocking is the one your garment will have.
What happens if my gauge is off by one stitch?
It adds up. At 22 stitches per 10 cm, a sweater with 220 chest stitches measures 100 cm. At 23 stitches per 10 cm, the same 220 stitches measure about 96 cm. One stitch in 10 cm changed the chest by 4 cm.
Should I match stitch gauge or row gauge?
Stitch gauge first. It sets the width, which is hard to fix afterwards. Row gauge sets the length, and most patterns give lengths in centimetres, so you can simply knit more or fewer rows.
Is gauge the same as tension?
Yes. British patterns call it tension, American patterns call it gauge. Both mean the number of stitches and rows in 10 cm (4 in).