Crochet gauge difference calculator

If your gauge does not match the pattern, the finished piece will not match the pattern's size, even if you follow every instruction. This calculator compares your swatch with the pattern's gauge, shows the percentage difference in stitches and rows, and predicts the width and length you will actually get, so you can decide whether to change hook, follow another size or recalculate before you start.

How to use the calculator

1. Choose inches (gauge per 4 in) or centimetres (gauge per 10 cm).
2. Enter the pattern's stitch gauge and, if it gives one, its row gauge.
3. Enter your own gauge over the same distance, from a blocked swatch. If you measured over a different width, get your per-4 in or per-10 cm figure from the gauge calculator first.
4. Enter the finished width (or chest) and length for the size you plan to make.
5. Choose Fitted garment or Blanket, scarf, bag to set how much difference is acceptable.

How the calculator works

The difference is how far your count is from the pattern's, as a percentage of the pattern's:

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

A positive difference means you fit more stitches into 4 in than the designer did: your stitches are smaller, so the piece comes out smaller. A negative difference means bigger stitches and a bigger piece.

Finished size scales the other way round from gauge, because you work the same number of stitches at a different width each:

Your width = pattern width × pattern stitches ÷ your stitches

Your length = pattern length × pattern rows ÷ your rows

That is why a 10% difference does not change the width by exactly 10%: 22 stitches instead of 20 multiplies the width by 20 ÷ 22 = 0.909, a 9.1% reduction.

The stitch difference is then checked against a tolerance: about ±2% for fitted garments and ±5% for blankets, scarves and bags. These bands are a planning guide, not a rule; the check uses stitch gauge, which controls width.

Reading your results

• Within tolerance: follow the pattern as written.
• Outside tolerance: change hook and swatch again (the swatch troubleshooter suggests which size), follow a different size of the pattern, or recalculate the counts for your gauge with the pattern gauge converter.
• Your finished length assumes you work the pattern's row count. If the pattern says "work until the piece measures…", the length will match and only the number of rows changes. The calculator says so when your stitches match but your rows are well off.

Worked example

A sweater pattern has 20 stitches and 28 rows per 4 in, for a 40 in chest and a 24 in length. Your blocked swatch has 22 stitches and 30 rows.

• Stitch difference: (22 − 20) ÷ 20 = +10%. Row difference: (30 − 28) ÷ 28 = +7.1%.
• Your chest: 40 × 20 ÷ 22 = 36.36 in, 3.64 in smaller than planned.
• Your length: 24 × 28 ÷ 30 = 22.4 in, if you work the pattern's row count.

You like the fabric and do not want to change hook. Enter the next size up, written for a 44 in chest: 44 × 20 ÷ 22 = 40.0 in. Following that size's stitch counts at your gauge gives the 40 in chest you wanted. Check the neck and armhole measurements of that size too, since they also change.

Accuracy and limits

• The arithmetic is exact and covered by our automated tests. It assumes you work the pattern's stitch and row counts unchanged.
• Row gauge matters more on shaped pieces, such as yokes and armholes, where shaping happens every so many rows.
• If you let the piece grow, it also uses more yarn: 10% wider and 10% longer is 21% more fabric. Check with the yarn yardage calculator.

Common mistakes

1. Comparing an unblocked swatch with a blocked pattern gauge. Most garment patterns give blocked gauge; measure your swatch the same way.
2. Forcing your tension to match. Pulling tighter or looser by hand rarely lasts beyond a few rows. Change hook or size instead.
3. Jumping several sizes. Following one size up or down works well for a modest gauge difference; across two or three sizes the neck and armholes may no longer suit you.

Tips for more accurate results

• Enter half stitches. 15.5 stitches against a pattern's 16 still adds 1.29 in to a 40 in sweater (40 × 16 ÷ 15.5 = 41.29).
• You can enter a flat panel width or a full circumference; the percentage and scaling work the same way.

Frequently asked questions