A pattern says "decrease 12 stitches evenly across the next row". The calculator below is set to that case: 84 stitches, 12 decreases, worked flat. Change the numbers and the line changes with them.
Why decreases need different math
An increase can add a stitch between two stitches. A decrease cannot. Each K2tog eats two stitches and leaves one. So 12 decreases use 24 of your stitches, and only the other stitches are worked plain between them.
The calculator takes those paired stitches out first. Then it spaces the plain stitches in equal runs. That is why a decrease line looks slightly different from an increase line for the same numbers.
The limit: half your stitches
You cannot decrease more than half the stitches in one row. At that point every stitch is part of a pair and the line is just K2tog across. If you need more, split the decreases over two rows. The tool shows the limit under the number box as you type.
Which decrease to use
K2tog leans right. SSK and SKP lean left. On a flat row, many knitters work K2tog on one side of the row and SSK on the other so the shaping looks even. This calculator spaces the changes. You choose the stitch under More options and the name in the line changes.
The same case in the round
With 84 stitches and 12 decreases in the round, the line is:
(K5, K2tog) 12 times.
Check: 12 K2tog and 60 K. You end with 72 stitches.
Nearby counts for 84 stitches
Other decrease counts for the same 84 stitches, on a flat row. The calculator wrote each line.
| Stitches | Remove | Pattern line | You get |
|---|---|---|---|
| 84 | −10 | K3, K2tog, (K6, K2tog) 3 times, (K7, K2tog) 4 times, (K6, K2tog) twice, K3 | 74 |
| 84 | −11 | K3, K2tog, (K5, K2tog) twice, (K6, K2tog) 6 times, (K5, K2tog) twice, K3 | 73 |
| 84 | −12 | K3, K2tog, K4, K2tog, (K5, K2tog) 10 times, K3 | 72 |
| 84 | −13 | K2, K2tog, (K4, K2tog) 3 times, (K5, K2tog) 6 times, (K4, K2tog) 3 times, K2 | 71 |
| 84 | −14 | K2, K2tog, (K4, K2tog) 13 times, K2 | 70 |
Questions
How many stitches can I decrease in one row?
At most half of them. Each decrease uses two stitches, so 84 stitches allow 42 decreases.
Should the first decrease be at the very edge?
No. On a flat row the calculator leaves about half a gap at each end, so the edge stitches stay plain and the seam stays neat.