Also commonly known as the Single Windsor, the Half-Windsor knot is not actually half the size of a Full or Double Windsor knot. Instead, the Half/Single and Full/Double modifiers refer to the number of times the the is wrapped prior to knotting.
The Half-Windsor produces a neat, triangular knot which is larger and fuller than a Four-in-Hand. There are two common variations on the Half-Windsor, one of which is self-releasing and one which is not. We've opted to demonstrate the more popular self-releasing knot for you here.
Begin with your shirt buttoned, collar turned up, and drape the tie around your neck with the narrow side on the right. The tip of the narrow side should be roughly level with your navel.
Take the wide end of the tie and bring it across the narrow end as shown.
Bring the wide end of the tie back behind the narrow end as shown.
Pinching the center to hold your wrap in place, bring the wide end back up.
Bring the wide end back through the main loop, keeping it on the left-hand side of the skinny end.
Wrap the wide end across the skinny end, pinching the center to hold the wrap in place.
Feed the wide end up through the back of the loop and prepare to come back down through the center of the knot.
Holding the wrap loosely in place, feed the wide end through the knot and start to tug it down.
In a simultaneous motion, pinch the knot up and tug the wide end of the tie down to tighten the knot. Ideally the tip of the wide end will rest between the top and bottom of your belt buckle. Bring the shirt collar down, smooth it out, and you're done!
If the tie is too short or too long, tug on the knot to undo it and simply start over. If your first attempt was too long, lengthen the narrow end in Step 1. If your first attempt was too short, shorten the narrow end in Step 1.