Crochet increases are worked into a stitch you already have, so the math differs from knitting. The calculator below is set for a round of 36 stitches with 6 increases, the kind of round you see in amigurumi and hats.
How an increase counts in crochet
"Inc" means two single crochet in the same stitch. The stitch you worked into is used, and it gives two. So each inc is one stitch of your count that ends up as two.
This is why "sc 5, inc" repeated 6 times covers 36 stitches and not 30. The line already counts the inc stitch as one of your stitches. The check under the pattern line shows the plain stitches and the increases so you can confirm it.
Flat or in the round
Most amigurumi and hat crowns are worked in the round. The tool then gives a short repeat to work all the way around, and you place a marker in the first stitch. For a flat piece such as a blanket border or a scarf, choose Flat rows. The first and last runs get half a gap, so no increase sits on the edge.
Other stitches
For half double or double crochet, use the same line and swap the stitch name. The spacing does not change. Work two of that stitch in the next stitch for each inc.
The same case on a flat row
With 36 stitches and 6 increases on a flat row, the line is:
sc 3, inc, sc 4, inc, (sc 5, inc) 4 times, sc 3.
Check: 6 inc and 30 sc. You end with 42 stitches.
Nearby counts for 36 stitches
Other increase counts for the same 36 stitches, in the round. The calculator wrote each line.
| Stitches | Add | Pattern line | You get |
|---|---|---|---|
| 36 | +4 | (sc 8, inc) 4 times | 40 |
| 36 | +5 | (sc 6, inc) 4 times, sc 7, inc | 41 |
| 36 | +6 | (sc 5, inc) 6 times | 42 |
| 36 | +7 | (sc 4, inc) 6 times, sc 5, inc | 43 |
| 36 | +8 | (sc 3, inc) 4 times, (sc 4, inc) 4 times | 44 |
Questions
What does inc mean in crochet?
It means two stitches worked into the same stitch. In single crochet, that is 2 sc in the next stitch.
Do I count the inc as one stitch or two?
Count the stitch you work into as one stitch of your current count. After the round, each inc gives you two, so you end with your count plus the number of increases.