Calculator
Gauge converter
Enter the pattern's gauge and yours. You get the percentage difference, the stitch count to work instead, and the yarn the change will cost you.
The maths, so you can check it
Stitch counts scale linearly with gauge: new = old × (your gauge ÷ pattern gauge). Yardage scales with the square of that ratio, because a wider fabric is also taller. A 10% tighter gauge therefore needs about 21% more yarn, not 10%.
This is the calculation almost nobody does. Most substitution advice stops at "match the weight category", which is why substituted projects so often come out the wrong size or run out of yarn two rows from the end.
When to recalculate and when to re-swatch
If you are within about 2%, knit the pattern as written. Between 2% and 5%, change needle size and swatch again — recalculating a whole pattern is more work than one more swatch. Beyond 5%, recalculate: the stitch counts will not land on the pattern's repeats otherwise, and you will be improvising shaping.
For sweaters and anything with set-in sleeves, recalculate rather than resize the needle — the armhole and shoulder maths assume the pattern's row gauge as well as its stitch gauge.
How to swatch so the number means something
Cast on at least 30 stitches, work in the pattern stitch for 12 cm, and measure across the middle 10 cm — never the edges, which curl and lie differently. Wash and block the swatch the way you will wash the finished object; most yarns relax by 5–10% and a gauge taken before blocking is a guess.
Measure in three places and average. If the three readings differ by more than half a stitch, the swatch is too small or the yarn is slippery — add stitches and try again. A gauge you cannot reproduce is worse than no gauge at all, because it sends you into the recalculation with a number that is not real.
What row gauge does to a garment
Stitch gauge decides width; row gauge decides length. Most patterns quote only stitches, which is why a sweater can come out the right width and three inches too long. If your row gauge is off by 10%, every "work until the piece measures" instruction still works, but every "work 40 rows" instruction does not — the armhole will sit in the wrong place and the sleeve cap will not fit.
The practical rule: when a pattern gives a length, trust the tape measure and ignore the row count. When it gives a row count for shaping — short rows, raglan increases, colourwork charts — recalculate the rows the same way you recalculated the stitches, using your row gauge divided by the pattern's.
Recalculating when the stitch pattern has a repeat
A cable or lace repeat of 8 stitches plus 2 means your new stitch count has to land on that multiple, or the pattern breaks at the seam. Take the recalculated number, divide by the repeat width, round to the nearest whole repeat, then add the edge stitches. The result will be a stitch or two off the pure ratio — that is correct, and it is why the calculator gives you a number to adjust rather than a number to cast on blindly.
For colourwork, round down rather than up: a slightly tighter fabric holds the floats better, and one repeat fewer is less visible than a stretched motif.
When not to recalculate
Do not recalculate a pattern you have not swatched in the round if the project is knitted flat, or vice versa — purl gauge and knit gauge differ, and the ratio you measured will be wrong. Do not recalculate a fitted garment with set-in sleeves unless you are comfortable redrawing the armhole; change needle size instead. And do not recalculate a pattern that is already written in your gauge — the arithmetic only adds error.
Questions people ask
How do I convert a pattern to my gauge?
Divide your stitches per 4 inches by the pattern's stitches per 4 inches to get a ratio, then multiply the pattern's stitch counts by that ratio. Yardage scales by the ratio squared.
What if my gauge is off by one stitch?
One stitch over 4 inches is roughly 4–5% — enough to change a finished size by a whole size. Either change needle size or recalculate.
Does gauge affect how much yarn I need?
Yes, and more than most people expect. A 10% tighter gauge needs about 21% more yarn, because the ratio is squared.