What This Calculator Does
The Cast-On Stitches Calculator tells you exactly how many stitches to cast on to reach a desired finished width, based on the gauge from your swatch. Gauge in knitting patterns is almost always given as the number of stitches over 4 inches (10 cm), so this tool uses that standard. Stop guessing or doing math in your head before you start a scarf, blanket, or sweater panel.
How to Use It
Enter the finished width you want in inches, then enter your gauge — the number of stitches you measured across 4 inches of your swatch. If your pattern uses edge or selvedge stitches (for example, a slip-stitch border), add those in the optional field and they'll be included in the total. The calculator rounds the base stitch count to the nearest whole stitch, because you can't cast on a fraction of a stitch.
The Formula Explained
The math is simple: $$\text{Stitches} = \operatorname{round}\!\left(\text{Width (in)} \times \frac{\text{Gauge}}{4}\right) + \text{Edge Stitches}$$ First we convert gauge to stitches per inch by dividing by 4. Then we multiply by the width to get a raw stitch count, round it to a whole number, and add any edge stitches. For stitch patterns with a repeat (like ribbing or cables), you may want to round the base count up or down to the nearest multiple of your repeat.
Worked Example
You want a scarf 8 inches wide and your gauge is 20 stitches per 4 inches. That's \(20 \div 4 = 5\) stitches per inch. \(8 \times 5 = 40\) stitches. With no edge stitches, cast on 40 stitches. If you add 2 garter-edge stitches per side, cast on 44.
FAQ
My gauge is in 10 cm, not 4 inches — is that a problem? No. 10 cm is the metric equivalent of 4 inches, so the same number works directly in this calculator.
Should I round up or down? The calculator rounds to the nearest stitch. If your stitch pattern needs a multiple (e.g. multiple of 4 for 2x2 rib), adjust the base count manually to the nearest valid multiple.
Why does my finished piece come out the wrong size? The most common cause is an inaccurate gauge swatch. Knit and block a generous swatch before measuring, and measure in the middle, not at the edges.
