An increase adds stitches to the next row or round. A decrease combines existing stitches into fewer new ones. Once you track how many stitches go in and how many come out, shaping instructions become much easier to check.
This guide uses US single crochet for the hands-on examples. Other stitches have their own decrease movements, and a pattern may define special shaping instructions.
A single-crochet increase: one becomes two
Work one single crochet into the next stitch, then work a second single crochet into that same stitch. You have used one old stitch and made two new ones. The stitch count increases by one.
Continue into the following stitch afterward. An easy mistake is to make the second single crochet in the next stitch instead of the same stitch. That gives two ordinary stitches, with no increase.
A single-crochet decrease: two become one
- Insert into the first stitch, yarn over and pull up a loop. Two loops are on the hook.
- Insert into the next stitch, yarn over and pull up a loop. Three loops are now on the hook.
- Yarn over and draw through all three loops to finish one combined stitch.
This is commonly written sc2tog. It uses two old stitches and produces one new stitch, so the count decreases by one. Skipping a stitch can also reduce a count, but leaves a different structure and is not a substitute unless directed.
Read the arithmetic before making the round
| Instruction | Old stitches used | New stitches made |
|---|---|---|
| Single crochet once | 1 | 1 |
| Two sc in the same stitch | 1 | 2 |
| Sc2tog | 2 | 1 |
| One sc, then an increase | 2 | 3 |
| One sc, then sc2tog | 3 | 2 |
For an original counting example, start with twelve stitches and repeat “one sc, increase” six times. Each repeat uses two old stitches and makes three new ones, giving eighteen stitches. The increase is six stitches overall, not twelve.
Reverse that change by working “one sc, sc2tog” six times over eighteen stitches. Each repeat uses three and makes two, returning to twelve.
What makes an invisible decrease different?
An invisible single-crochet decrease usually works through the front loops of two neighboring stitches before completing the combined stitch. It is common in amigurumi worked with the right side facing out, where the placement can make the decrease less conspicuous.
It is not automatically the best choice for every fabric. In turned rows, reversible items or a pattern that specifies a regular decrease, the surface effect and orientation matter. Follow the designer’s method and practice on the same type of fabric.
Place shaping where the pattern puts it
Getting the final total right is necessary, but the placement also creates the shape. Six increases all together do not produce the same fabric as six increases spread around a round. Moving them changes the result even if the count still matches.
Mark repeats when needed. If the pattern separates shaping from ordinary stitches, check each section as well as the total. This helps you locate an error without recounting the entire piece repeatedly.
When a circle cups or ruffles
Too few increases can contribute to cupping; too many can contribute to waves. Tension, stitch height and yarn also matter, so do not add or remove increases at random to flatten a shaped object.
A bowl, hat crown or toy may be intended to curve. Compare the pattern’s expected stage and counts before “correcting” that shape. A practice circle teaches the arithmetic, while a complete project needs its designed shaping sequence.
Check before moving on
Count from a marked first stitch, exclude joins and starting chains when the instructions exclude them, and record the completed round. Catching a missed increase now is much easier than finding it several rounds later when the shape no longer fits the next section.
Keep learning
Review single crochet · Start a round · Count stitches accurately