How do I decrease 10 stitches evenly across 100?

Ten K2tog use 20 of the 100 stitches, which leaves 80 to knit plain. 80 divided by 10 is 8, so there are 8 plain stitches per decrease. On a flat piece half a gap goes at each edge: K4, *K2tog, K8; rep from * 8 more times, K2tog, K4. That works all 100 stitches and leaves 90.

How do I increase evenly in the round?

Divide the stitches by the number of increases. For 8 M1 increases on 96 stitches that is 12: *K12, M1L; rep from * 7 more times, giving 104 stitches with every increase 12 stitches from the next, including across the start of the round. With KFB, which uses up a stitch itself, it is *K11, KFB.

How many stitches do I pick up along a side edge?

Knitted stitches are wider than they are tall, so one stitch per row makes the band ruffle. The common rule of thumb is three stitches for every four rows (pick up 3, skip 1), so 60 rows give 45 stitches. Your own gauge gives a closer number: stitches per 10 cm divided by rows per 10 cm, times the rows. In garter stitch, one per ridge (two rows).

Knitting calculator

Increase or decrease evenly, written out and balanced. Gauge, cast-on and pick-up below.

Increase or decrease evenly

Stitches now Decrease by Method

Gauge

Pattern sts Pattern rows Your sts Your rows Pattern says (sts) Pattern says (rows)

Cast on for a width

Width (cm) Sts Multiple of Plus (edge sts)

A rib of K2, P2 with a stitch each side is a multiple of 4 plus 2. Width is in cm, matching the gauge.

Pick up stitches along a side edge

Rows along the edge

Uses “Your sts” and “Your rows” from the gauge box. A pattern that gives its own pick-up count wins over both.

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How the even spacing is worked out

Each shaping stitch uses up some of the stitches on the needle: K2tog and SSK work two stitches into one, KFB works one stitch into two, and M1L or M1R makes a stitch from the strand between two stitches without using one. So the stitches left to knit plain are the stitches you have minus the ones the shaping uses, and they are shared out between the shapings as evenly as whole stitches allow. Where they do not divide exactly, some gaps are one stitch longer than the rest.

Flat, decrease 10 from 100 with K2tog. Ten K2tog use 20 stitches; 80 are left to knit plain, 8 per decrease. One gap is split between the two edges, so the shaping sits away from the seams: K4, *K2tog, K8; rep from * 8 more times, K2tog, K4 (90 sts). That is 4 + 9 × 10 + 2 + 4 = 100 stitches worked.
Flat, decrease 7 from 87. 87 − 14 = 73 plain stitches do not divide by 7 (10 rem 3), so three gaps are 11 and the rest 10: K5, [K2tog, K11] 3 times, [K2tog, K10] 3 times, K2tog, K5 (80 sts).
In the round, increase 8 on 96 with M1L. M1 uses no stitches, so 96 ÷ 8 = 12: *K12, M1L; rep from * 7 more times (104 sts). The last increase is 12 stitches before the first one of the next round, so the spacing is even all the way round. Flat work is different: there the gap is split between the two edges, because the edges are sewn into seams and do not meet.
KFB counts the stitch it is worked into. 8 KFB on 96 in the round is *K11, KFB; rep from * 7 more times: each repeat still covers 12 of the old stitches.

Limits: one row can decrease at most half its stitches with K2tog or SSK (every stitch in a K2tog), and the page will not increase more than one stitch per stitch. Ask for more and it says so instead of writing a row you cannot knit. Double decreases (K3tog, CDD) are not offered.

Gauge, cast-on and pick-up formulas

Gauge. Your stitches = pattern stitches × your gauge ÷ pattern gauge. A pattern at 22 sts per 10 cm that casts on 110 wants 50 cm; at your 20 sts per 10 cm, cast on 110 × 20 ÷ 22 = 100 for the same 50 cm. Knit the pattern's 110 at your gauge and the piece is 55 cm, 10 % wider. Rows work the same way, but most patterns give lengths in cm, which need no conversion.
Cast on for a width. Width × stitches per 10 cm ÷ 10 (or per 4 in ÷ 4) gives the raw count, which is then moved to the nearest count that fits the stitch pattern: multiple × a whole number + edge stitches. 52 cm at 18 sts per 10 cm is 93.6; with a multiple of 4 + 2 the choices are 90 (50 cm) and 94 (52.2 cm).
Pick up. From your gauge: rows × stitches per 10 cm ÷ rows per 10 cm. At 20 sts and 28 rows, 60 rows want 43 stitches. The rule of thumb is 3 for every 4 rows, 45 here, worked as “pick up 3, skip 1”.

Where the 3-for-4 rule comes from

Knitted stitches are wider than they are tall, so picking up one stitch for every row along a side edge makes too many stitches and the band ruffles. The Wikipedia article Pick up stitches (knitting) (fetched 2026-10-20), which cites June Hemmons Hiatt's The Principles of Knitting (1988), puts it this way: As a rule of thumb, picking up three stitches for every four rows will avert this problem. When the main fabric is in garter stitch, one picked-up stitch for every garter ridge (i.e. two rows) will generally suffice. Quince & Co.'s techniques: picking up stitches (fetched 2026-10-20) gives the working method: pick up three stitches, then skip one space; repeat. It is a starting point for stockinette at an average gauge; the count from your own gauge is usually closer, and a pattern's own number beats both.

What it cannot do

Lace, cables and colourwork change gauge. Cables pull a fabric in, lace opens it out, and stranded colourwork is usually tighter than plain stockinette. Swatch in the stitch you will use; a stockinette swatch will give the wrong numbers.
It does not write whole patterns. It writes one shaping row, converts numbers, and rounds a cast-on. Sleeve tapers spread over many rows, yokes, short rows and charts are not covered.
No crochet. Crochet stitches have a different height-to-width ratio and different increases; these numbers do not apply.
Increases and decreases only one stitch at a time. No K3tog, CDD, or double increases.

Questions

What do K2tog, SSK, M1L, M1R and KFB mean?

K2tog: knit two together, a decrease that leans right. SSK: slip, slip, knit, a decrease that leans left. M1L / M1R: make one, a new stitch lifted from the strand between two stitches, leaning left or right; almost invisible. KFB: knit into the front and back of one stitch, which leaves a small purl bump. K8 means knit 8, and *…; rep from * 8 more times means work that part 9 times in all; […] 3 times means 3 times in all.

Why are the stitches at the two ends different from the gaps?

On a flat piece the outer stitches become seams or edges. Putting half a gap at each end keeps the shaping balanced across the piece and away from the seam. In the round there are no ends, so every gap is a full gap.

Do I count the selvedge stitches?

Type the stitches you have on the needle, all of them. If your pattern has a slipped or garter edge stitch you do not want to shape over, subtract those stitches before typing, then knit them at each end.