How to Crochet a Half Circle (Semicircle Shaping)

A half circle, or semicircle, is a useful and pretty shape in crochet, used for shawls, fans, collars, and baby items. It is essentially half of a flat circle, worked in rows instead of rounds, and it follows the same increase logic that keeps a circle flat. Once you understand how the increases are spaced, a half circle is straightforward to make. This guide shows you how to crochet a half circle that lies nice and flat. It is part of the crochet shapes guide.

What Is a Half Circle?

A half circle is exactly what it sounds like, half of a flat circle, with a straight edge along the diameter and a curved edge around the arc. Unlike a full circle, which is worked in continuous rounds, a half circle is worked in rows, turning at the end of each row, because you only go half way around. As the rows build up, the fabric fans out from the straight edge into a semicircle. It relies on the same even increasing that keeps a full circle flat, just applied over half the shape.

The Increase Rate for a Half Circle

Because a half circle is half a circle, it needs about half the increases per row that a full circle needs per round. A flat single crochet circle adds six stitches every round, so a single crochet half circle adds about three stitches every row, spaced evenly across, to keep the semicircle flat. Taller stitches need more, following the same pattern as the crochet circle formula. Getting this rate right is the key to a flat half circle, since too few increases make it cup and too many make it ruffle.

Step by Step: How to Crochet a Half Circle

Step one: start with a few stitches, often worked into a chain or a half of a magic ring, following your pattern. Step two: turn, and on the next row increase evenly across, adding your stitches spread out along the row. Step three: continue turning and increasing on each row, spacing the increases evenly and staggering them so they do not stack. Step four: as the rows build, the fabric fans out into a semicircle. Continue until the half circle is the size you want, keeping the increase rate steady, then fasten off.

Keeping It Flat

Just like a full circle, a half circle only lies flat when the increases are spaced correctly and evenly. If it cups upward, you are increasing too slowly, so add a few more increases per row. If the curved edge ruffles, you are increasing too fast, so use fewer. Stagger the increase points from row to row so they spiral rather than stacking into corners, and count each row. These are the same flatness principles covered in why crochet circles curl, applied to the semicircle.

Common Half Circle Mistakes

The most common mistakes are using the wrong increase rate, so the half circle cups or ruffles, and stacking increases directly on top of each other, which creates angular points instead of a smooth curve. Match the increase rate to half the full circle number for your stitch, and stagger the increases. Losing your stitch count also distorts the shape, so count each row against what you expect. The crochet shape troubleshooting guide covers fixes for all of these.

What You Can Make

Half circles are used for half circle shawls, which drape beautifully around the shoulders, as well as fans, collars, baby bibs, bonnets, and decorative motifs. The half circle shawl is a favorite because it is easy to wear and shows off stitch patterns and color changes well. For the full round version, see how to crochet a circle, and to turn a circle into a three dimensional form, see how to crochet a bowl. Find projects in the beginner pattern hub.