Evenly Spaced Increase & Decrease Planner

To spread a number of increases or decreases evenly over a round or a row, subtract the stitches the changes use up, divide what is left into gaps between the changes, and share out the remainder. 96 stitches with 12 decreases comes to (k6, k2tog) x 12 and leaves 84. The planner on this page does the sum for rounds and flat rows, in knitting and US crochet abbreviations.

How do you space decreases evenly around a round?

Count what the decreases use, then divide the rest. A decrease works two stitches into one, so 12 decreases use 24 of 96 stitches. The other 72 stay plain, and 72 divided by 12 gives a gap of 6 plain stitches before each decrease: (k6, k2tog) x 12. Check it: each repeat is 6 plain stitches plus 2 for the decrease, 8 in all, and 12 repeats come to 96. The round ends at 84.

That is the whole method. Everything else on this page is what to do when the division does not come out even, when the work is flat, and when the change is an increase.

Counting stitches to make a shape is an old habit. A pattern book printed in Paris in 1587 and 1588 editions prints a lion as a grid and says it is 59 meshes high, as Teazle's find on it describes.

What do k2tog, ssk, kfb, m1 and sc2tog mean?

Each is a way of changing the stitch count in knitting or crochet, and each takes a different number of stitches from the row. According to Wikipedia's list of knitting abbreviations, k2tog means to knit two stitches together, a right-leaning decrease. Ssk slips two stitches knitwise one at a time and knits them together through the back loops, a left-leaning decrease.

For increases, kfb knits into the front of a stitch and then into the back of the same stitch before it leaves the left needle, as the Knotions tutorial describes it, so one stitch becomes two. M1, make one, is different: you pick up the bar between two stitches and knit into it, which Noble Knits says makes a new stitch that looks as if it was always there. It adds a stitch without using one.

Crochet has the same pair. Wikipedia's list of crochet stitches describes an increase as two or more stitches worked into the same stitch, and a decrease as one stitch worked across two or more. The single crochet decrease is written dec, sc-dec or sc2tog; Handy Little Me explains that sc2tog, single crochet two together, combines two single crochets into one stitch.

The first column of the table is what the planner subtracts before it divides. A decrease takes two, so 12 of them take 24. A kfb takes one, so 12 take 12. An m1 takes none, so every stitch stays plain.

What if the numbers do not divide evenly?

Some gaps get one stitch more. Take 100 stitches and 12 decreases. The decreases use 24, leaving 76 plain stitches. Divided by 12 that is 6 with 4 left over, so four of the twelve gaps hold 7 stitches and eight hold 6.

Where the long gaps go matters. Putting all four at the end would leave a lump of plain knitting in one place. The planner instead places the boundary after each gap at the rounded-down value of its position times 76, divided by 12. That spreads the long gaps as evenly as whole stitches allow and gives a short repeat: [(k6, k2tog) x 2, k7, k2tog] x 4. The gaps add to 76, the decreases to 24, and the round ends at 88.

Spreading whole numbers evenly is an old problem in computing. Bresenham's line algorithm, developed by Jack Bresenham at IBM in 1962, picks the screen pixels that best approximate a straight line, and Wikipedia notes it uses only integer addition, subtraction and bit shifting. The planner is in the same family: only whole-number arithmetic, so the same input always gives the same answer. It is not Bresenham's algorithm itself.

How is a flat row different?

A flat row has two ends. Most patterns keep an edge stitch at each end, and the first and last gap touch a decrease on one side only, so the planner counts each as half a gap. It also rounds so that the gaps read the same from both ends.

Take 50 stitches with an edge stitch at each end and 7 decreases. That leaves 48 working stitches, 14 of them used by the decreases, so 34 are plain. Thirty-four plain stitches over seven gaps' worth (six between the decreases and two half gaps at the ends) is 4.86 per gap, which rounds to gaps of 2, 5, 5, 5, 5, 5, 5, 2. Adding the edge stitches to the ends gives the row as k3, (k2tog, k5) x 6, k2tog, k3. It ends at 43. If the number of plain stitches is odd and the row has an even number of gaps, one stitch has no partner. The planner puts it right of center and says so.

There is also an option to work the first and last decrease right beside the edge stitches instead of leaving plain stitches at the ends, and a choice of k2tog, ssk, or k2tog on the left half with ssk on the right.

What happens with increases, and how many can one row take?

The sum is the same with a different count of stitches taken. Sixty stitches with 8 kfb leaves 52 plain, 6 with 4 over: [k6, kfb, k7, kfb] x 4, ending at 68. With m1 nothing is used, so all 60 stay plain, 7 with 4 over: [k7, m1, k8, m1] x 4. Both end at 68, but the gaps differ by a stitch, which is why the choice matters when a pattern specifies one.

A row has limits. A decrease uses two stitches, so at most half the working stitches can be decreased at once: 20 stitches take at most 10. Asked for 11, the planner refuses and shows how to split it, 10 in the first round and 1 in the next. Increases can at most double the stitches.

What does the planner not know?

It counts stitches, not rows, and it does not know your stitch pattern, so in lace or cables you may need to move a change to suit the repeat. Whether a row is knit or purl changes the abbreviations: on a purl row read k2tog as p2tog and kfb as pfb. Crochet counts exclude the turning chain, and the crochet abbreviations here are US ones: if your pattern was written in the UK system, read this first. Gauge decides how large the finished stitches are; see gauge.

The tool is free to use and everything runs in your browser. For the arithmetic of each case above, the page's own tests check that the written instruction always uses all the stitches you started with and leaves the count you asked for.