Materials needed:

Worsted weight yarn (color of your choice)
Crochet hook (size appropriate for your yarn)
Scissors
Yarn needle

Pattern:

Note: This pattern is written in U.S. crochet terminology.

Step 1: Starting Chain Chain 4, slip stitch into the first chain to form a ring.

Step 2: Round 1 Chain 2 (counts as first double crochet), work 11 double crochets into the ring. Slip stitch into the top of the beginning chain-2 to join. (12 stitches)

Step 3: Round 2 Chain 2 (counts as first double crochet), work 2 double crochets into each stitch around. Slip stitch into the top of the beginning chain-2 to join. (24 stitches)

Step 4: Round 3 Chain 2 (counts as first double crochet), work 1 double crochet into the next stitch, 2 double crochets into the following stitch. Repeat from * to * around. Slip stitch into the top of the beginning chain-2 to join. (36 stitches)

Step 5: Round 4 Chain 2 (counts as first double crochet), work 1 double crochet into the next 2 stitches, 2 double crochets into the following stitch. Repeat from * to * around. Slip stitch into the top of the beginning chain-2 to join. (48 stitches)

Step 6: Rounds 5 to desired length Chain 2 (counts as first double crochet), work 1 double crochet into each stitch around. Slip stitch into the top of the beginning chain-2 to join. Repeat this round until the hat measures the desired length, usually around 6-7 inches (15-18 cm) for an adult hat. You can adjust the length to fit the wearer.

Step 7: Decrease Rounds Switch to a smaller crochet hook size if desired for a snugger fit.

Round 1: Chain 1, work 1 single crochet into each stitch around. Slip stitch into the first single crochet to join. (48 stitches)

Round 2: Chain 1, work 1 single crochet into the next 2 stitches, work 2 single crochets together. Repeat from * to * around. Slip stitch into the first single crochet to join. (36 stitches)

Round 3: Chain 1, work 1 single crochet into the next stitch, work 2 single crochets together. Repeat from * to * around. Slip stitch into the first single crochet to join. (24 stitches)

Round 4: Chain 1, work 2 single crochets together in each stitch around. Slip stitch into the first single crochet to join. (12 stitches)

Step 8: Finishing Cut the yarn, leaving a long tail. Thread the tail through a yarn needle and weave it through the remaining stitches. Pull tight to close the top of the hat. Fasten off and weave in any loose ends.