Knitting Gauge Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 28, 2026Knitting Gauge Calculator
Adapting a pattern or designing your own piece? This calculator converts your gauge swatch measurement into the correct cast-on count.
Stitches Per Inch = Stitches in Swatch / Swatch Width(in)
Stitches to Cast On = Stitches Per Inch x Target Finished Width(in)
Example
20 stitches counted across a 4-inch swatch, targeting a 40-inch finished width:
Gauge = 5.00 stitches/inch → Cast on 200 stitches
Why Swatching Is Non-Negotiable
Always knit and measure a gauge swatch before starting a garment - individual knitting tension varies significantly between knitters even when using the identical yarn and needle size, which is exactly why patterns list a target gauge to match rather than a fixed universal stitch count for a given finished size.
Wash Your Swatch Before Measuring
Washing and blocking the gauge swatch the same way the finished piece will eventually be cared for, before measuring it, gives a far more accurate gauge than measuring straight off the needles - many yarns relax or tighten noticeably after their first wash.