Crochet gauge troubleshooter

When your swatch does not match the pattern, there are two common causes: your tension is tighter or looser overall, or your stitches are the right width but a different height. They need different fixes. This troubleshooter compares your stitch and row gauge with the pattern's, tells you which problem you have, and names the next hook size to swatch with.

How to use the troubleshooter

1. Enter the size of the hook you made the swatch with, in millimetres. If your hook only shows a US letter or an old UK number, look it up in the hook size converter.
2. Enter the pattern's stitch and row gauge over 4 in (10 cm).
3. Enter your stitch and row gauge over the same distance, from a blocked swatch. If you measured over another width, convert it with the gauge calculator first.
4. Swatch again with the suggested hook and re-enter the new numbers.

How the troubleshooter works

It first works out how far your stitches and rows are from the pattern, as percentages:

Stitch difference = (your stitches − pattern stitches) ÷ pattern stitches × 100

Then it sorts the result:

• Both within 0.5%: an exact match. Keep your hook.
• Stitches within 3% but rows more than 6% off: keep the hook. The width is right; the difference is in how high you pull up each loop, often called the golden loop. Pull the loops a little taller if you have too many rows, or keep them snugger if you have too few. Or simply work to the measured length.
• Stitches off: change hook. More stitches than the pattern means your stitches are too small, so go up a size; fewer stitches means go down.

For the size of the change it uses a rule of thumb from the research behind these calculators: about 0.5 mm for every 6.5% difference in stitch gauge, rounded to the nearest 0.5 mm, never more than 2 mm either way, and matched to a standard hook size.

Hook change = stitch difference ÷ 6.5 × 0.5 mm

Reading your results

• Diagnosis: tighter than the pattern, looser, close enough, or a row-only difference.
• Next swatch: the hook to try. When the change is 1 mm or more, it names the next 0.5 mm step first and then the target, so you do not overshoot.
• Stitches / rows: your differences as percentages. If they point in opposite directions, a note explains what that means for your loops.

Worked example

A cardigan pattern asks for 16 stitches and 18 rows per 4 in on a 5 mm (US H-8) hook. Your swatch on that hook has 18 stitches and 20 rows.

• Stitches: (18 − 16) ÷ 16 = +12.5%. Rows: (20 − 18) ÷ 18 = +11.1%. Both are tight.
• Hook change: 12.5 ÷ 6.5 × 0.5 = 0.96 mm, rounded to 1 mm.
• Next swatch: try 5.5 mm (US I-9), then 6 mm (US J-10).

Accuracy and limits

• This is a planning aid, not exact maths. Hook size and gauge are not proportional: the same 0.5 mm step changes a small hook's gauge more than a large one's.
• Small hooks come in 0.25 mm steps (3.25, 3.5, 3.75 mm). The suggestion is rounded to 0.5 mm, so on a fine yarn try the quarter size in between first.
• Stiff fibres such as linen, hemp and mercerised cotton react differently from springy wool.
• If you would need more than 2 mm of change, the yarn is probably the wrong weight for the pattern. Keep the hook that makes good fabric and recalculate with the pattern gauge converter.
• Always swatch again after changing hook.

Common mistakes

1. Going down a size when you have too many stitches. Too many stitches means they are too small; a smaller hook makes them smaller still. More stitches: go up. Fewer stitches: go down.
2. Changing hook type without swatching. A slick metal hook and a grippy wooden one of the same size can give different gauge.
3. Squeezing the yarn to fix a big difference. Small tension tweaks rarely last for a whole project. Let the hook do the work.

Tips for more accurate results

• Work the new hook on the same swatch, separated by a row in a contrasting colour, so you can compare both fabrics after blocking.
• Before swatching again, check the gauge difference calculator: following another size of the pattern may already give you the measurements you want.

Frequently asked questions