If you can make the chain stitch and the single crochet stitch, you can make a round rug to fit any room in your home. The difference between a crocheted drink coaster and a crocheted rug is just the size of the yarn and the size of the hook. Bulky-weight acrylic or cotton yarn creates a thick, warm crocheted rug with the added bonus of being machine washable. Best of all, because you crochet from the center out, you can make your rug any size you want it to be -- just stop crocheting when it's big enough.
Chain four stitches. Connect the first and last stitch in the chain with a slip stitch to close the loop.
Work eight single-crochet stitches into the center of the ring.
Join the first and last stitch with a slip stitch at the end of this round and every following round. Start every new round by chaining two stitches, which counts as the first single-crochet stitch.
Work a single crochet stitch into the first single crochet stitch of the third round and every round that follows.
Make two single-crochet stitches in every remaining single-crochet stitch of the previous round to complete round 3.
Work one single-crochet stitch into the first stitch of round 4, two single-crochet stitches into the second stitch, one single-crochet stitch into the third stitch, two single-crochet stitches into the fourth stitch, and so on.
Work one more single-crochet stitch before increasing on each round that follows. For example, in row 5, work two single-crochet stitches in two consecutive single-crochet stitches from the previous round and increase on the third stitch. In row 6, work three consecutive single-crochet stitches before increasing. In row 7, work four consecutive single-crochet stitches before increasing.
Continue in this pattern until the rug is as large as you want it to be. Join the first and last stitches of the last round with a slip stitch and cut the working yarn, leaving a 3-inch tail. Weave the tail along the outer edge of the rug with your fingers. Tuck the end of the tail into a stitch on the underside of the rug to keep it from showing.