This pattern for is for toe-up socks with stranded colourwork.

You can use any fingering weight yarns of any 2 contrasting colours but green and grey are the colours for Slytherin.

The sizes are for the circumference of the foot, you can then knit the socks for any length needed.

For mid-calf socks a 50g skein of each color is enough (210m each)

The pattern is made using needles in sizes: 2.0 mm / US 0 and 2.5 mm / US 1½ but you may need/want to try other needles to obtain the correct gauge or size.

If you knitting a gauge swatch do it following one of the colourwork charts and in the round.