What this calculator does
This tool converts a knitting gauge into the exact stitch and row counts you need for a finished piece. A gauge is measured by knitting a small test swatch and counting how many stitches fit across 10 cm and how many rows fit down 10 cm. Because gauge is referenced to the international standard 10 cm by 10 cm square, this calculator is universal and works with any yarn, needle size or pattern.
How to use it
Knit and lightly block a swatch, then count your gauge over a 10 cm window. Enter the stitches per 10 cm and rows per 10 cm. Next, type the finished width (the stitch direction) and finished height (the row direction) in centimetres. The calculator instantly shows how many stitches to cast on and how many rows to work, both rounded to the nearest whole number.
The formula explained
The math is a simple proportion. Since gauge is per 10 cm, the number of stitches you need equals your stitch gauge multiplied by the width divided by 10:
$$\text{Stitches} = \text{round}\left(\text{gaugeStitches} \times \frac{\text{width}}{10}\right)$$Rows follow the same logic with your row gauge and the height. Results are rounded half-up to a whole stitch or row, since you cannot knit a partial stitch.
$$\begin{gathered} \text{Stitches} = \left\lfloor \text{Stitches / 10 cm} \cdot \frac{\text{Width (cm)}}{10} + 0.5 \right\rfloor \\[1.2em] \text{Rows} = \left\lfloor \text{Rows / 10 cm} \cdot \frac{\text{Height (cm)}}{10} + 0.5 \right\rfloor \end{gathered}$$
Worked example
Suppose your swatch gives 32 stitches and 46 rows per 10 cm, and you want a piece 20 cm wide and 50 cm tall.
$$\text{Stitches} = \text{round}\left(32 \times \frac{20}{10}\right) = \text{round}(64) = \textbf{64 stitches}$$$$\text{Rows} = \text{round}\left(46 \times \frac{50}{10}\right) = \text{round}(230) = \textbf{230 rows}$$FAQ
Why must the gauge be per 10 cm? The 10 cm square is the international knitting standard, so the formula divides by 10. If you measured over a different size, your result will be inaccurate.
Why are the answers rounded? You can only cast on whole stitches and knit whole rows, so the calculator rounds to the nearest integer using round-half-up.
Does it work in inches? This version uses centimetres for dimensions; convert inches to cm \(1\text{ inch} = 2.54\text{ cm}\) before entering them.
