How to Calculate Pattern Multiples

Okay, it's time for some crochet math!

Wait! Come back! It won't be that hard, I promise!

Sometimes you might want to make a crochet pattern a different size than the pattern dictates. This is especially common for afghans. The pattern might be for a baby afghan, but you'd like to make an adult-size afghan, for instance. Really helpful pattern writers will include a line stating what the multiple for the pattern is. This is usually given as something like "chain a multiple of 4 + 2," which means to make a number of chain stitches that is a multiple of 4, then chain 2 more. This is often abbreviated as "mult 4 + 2."

If the pattern doesn't tell you what the multiple is, though, can you figure it out for yourself?

Yes! To figure out the multiple, you need to count the chains used in the pattern repeat. Let's use the following pattern snippet as an example.

The pattern starts:

Chain 133.
Row 1: work shell (3dc, ch1, dc) in 6th chain from hook, *skip next 3 chs, work shell in next ch; repeat from * across to last 3 chs, skip next 2 chs, dc in last ch; 32 shells.

The pattern repeat in this pattern is the part between the *'s:
*skip next 3 chs, work shell in next ch; repeat from *
This tells you to skip 3 chains, then do a shell in the 4th chain, so the repeat uses four chains.

Next, you need to add the chains at the beginning and the end of the first row:
work shell (3dc, ch1, dc) in 6th chain from hook
and
across to last 3 chs
So you need 6 chains at the beginning and 3 chains at the end, or 9 total. Thus your starting chain is 9 chains plus a multiple of 4, usually written:
multiple of 4 plus 9
or
mult 4 + 9

In the example, the starting chain was 133, which is 124 + 9, or (31 * 4) + 9. The (31 * 4) is 31 shells. The 32nd shell is the first one in the 6th chain.

Sometimes you need to look at the second or third or later rows to be sure about your repeat. For example, you might need, say, an even number of shells to work the second row. If so, you'd still have the same repeat (mult 4 + 9), but you'd have to figure out how many shells you want first. If you wanted 16 shells instead of the original 32, do this: Remember that the + 9 part includes one shell, so you need to figure out only the number of stitches needed for 15 shells. This would be 15 * 4, or 60. So you'd need (15 * 4) + 9 or 60 + 9 or 69 stitches.

There now, that wasn't so bad, was it?