Single crochet vs double crochet
Single and double crochet differ in height, in firmness and in what they are for. When a pattern uses one rather than the other, and why.
Single crochet is the shorter of the two and the firmer: hook in, yarn over, draw up a loop, yarn over, through both loops on the hook. Two loops, one pull, and the stitch closes tight against its neighbours. That fabric is what a stuffed piece needs, because the filling has nowhere to show through, and what a cloth needs, because it will take scrubbing. Double crochet begins with a yarn over before the hook goes in, carries three loops, and clears them in two pulls. It stands roughly twice as tall in worked fabric, so half as many rows cover the same span, and it leaves small regular gaps that let the fabric fall. Learn single crochet first — the motion is one step shorter, and most first patterns use it alone. Learn double crochet next, and almost everything else opens up.
Where single crochet earns its place
Count the loops and the difference is already there. Single crochet never carries more than two loops on the hook, so the stitch is closed almost as soon as it is begun, and its top sits directly on the row below with barely any post between them. The result is a fabric with very little air in it.
That is exactly what a stuffed piece is after. Worked on a hook half a millimetre under the ball band's, single crochet closes tightly enough that polyester filling stays behind it, and a round of it can be counted back weeks later because every stitch has held its shape. Cloths and baskets want the same firmness for a different reason — they have to survive being wrung out or filled.
The cost is rows. A hand's span of single crochet is a great many rows, and the fabric will not hang: put it on a rail and it stands there. That is a defect in a shawl and the whole point in a creature.
What double crochet buys
Double crochet buys height with one extra yarn over. Because the stitch works up to roughly twice the height, half as many rows cover the same span, and a blanket that would be a season's work becomes a few evenings' work. The posts also hold the fabric slightly apart, and that space is where the fall comes from.
Almost every square in the tradition is built on it. The classic granny round is clusters of three double crochet with a chain between them, and it works because the stitch is tall enough to give the corner chain something to turn around. Garments follow for the same reason: the fabric falls instead of standing.
The trade is definition. A double crochet stitch is a post with a gap beside it, so a colour change reads a little softer, and a stuffed piece worked in it looks lumpy and lets its filling show at the gaps. Height and firmness are one dial turned two ways.
| In practice | Single crochet (sc) | Double crochet (dc) |
|---|---|---|
| Yarn over before the hook goes in | No | Yes, once |
| Loops carried on the hook | 2 | 3 |
| Pulls to close the stitch | 1 | 2 |
| Turning chain | 1 | 3 |
| Fabric | Close and firm | Open, softer |
| Rows to cover a span | More | About half |
| Yarn per stitch | Less | More |
| Drape | Holds its shape | Falls |
| Used for | Creatures, cloths, anything stuffed | Blankets, squares, garments |
| In a UK book | Double crochet (dc) | Treble (tr) |
Turning chains, and why the two differ
At the end of a row the hook has to climb to the height of the next one before the first stitch can be made, and the chain that does the climbing is not the same length for both stitches. Single crochet turns on chain 1, and that chain does not count as a stitch: work the first single crochet into the very first stitch of the row below, or the row loses one on every turn. Double crochet turns on chain 3, and that chain usually does count as the first double crochet: skip the stitch directly below it and work into the next one.
Getting it backwards is the commonest reason a rectangle comes off the hook as a trapezium. Count the stitches at the end of every row for the first few rows of any new pattern — if the number falls by one a row you are eating the turning chain, and if it rises by one you are working into it as well as past it. A pattern that departs from the two defaults above says so in the round it departs on.
Working the two together
Alternating whole rows is the simplest mix and it shows plainly: a row of single crochet under a row of double crochet leaves a horizontal ridge where the short stitches pull the tall ones in. A fabric made of those ridges has more body than double crochet alone without the row count of single crochet alone.
Ripples give the two different jobs. Double crochet clusters do the climbing and the falling; single crochet sits at the turn and holds the shape so the peak does not spread. On a square, a round of single crochet worked around a double crochet field makes a firm border that stops the edge ruffling — the same trick, used to stiffen rather than to decorate.
If you are substituting rather than combining, the arithmetic is roughly two to one and it is never clean. Two single crochet rows stand about as tall as one of double crochet, so the row count doubles, the fabric turns firm, and the finished measurement will not match what the pattern promised.
Common questions
Which of the two covers ground faster?
Double crochet, by roughly half the rows for the same height. Each stitch takes a moment longer to make and covers about twice as much ground, so the row count falls faster than the per-stitch time rises.
Which stitch belongs on a first page?
Single crochet. It has one fewer step than double crochet, the fabric is firm enough that you can see exactly what you did, and most first patterns use it alone.
May double crochet go where a pattern asks for single?
Not without changing the finished piece. Roughly two rows of single crochet stand as tall as one of double crochet, so the row count doubles, the fabric turns firm and the measurement drifts. Where a pattern allows the swap, it says so.
A UK pattern says dc — which stitch is that?
Double crochet in a UK pattern is the stitch a US pattern calls single crochet. The two sets of terms are one step apart the whole way up — the conversion page has all of it.
Why is nearly every blanket set in double crochet?
Three things at once: half the rows, a fabric that falls rather than stands, and small regular gaps that keep the weight down. The same blanket in single crochet is stiffer and takes far longer.
Does a stuffed piece have to be single crochet throughout?
Yes, and on a hook under the ball band's size. Double crochet leaves posts and gaps, and filling finds both.