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Increase or decrease evenly calculator

Space increases or decreases evenly across a row or round and get stitch-by-stitch instructions you can follow, in US or UK terms.

Built by Monhar Wesvakguide edited by Alice Jackie

Blue crochet circle with coloured stitch markers spaced evenly around the edge, a wooden hook and blue yarn
Stitch terms
More than now to increase, fewer to decrease.
Working
Rows keep the shaping away from both edges.

Your result

Exact maths

Fill in the fields above to see your result.

Exact arithmetic from the numbers you entered. Your tension, yarn and blocking still decide the real fabric.

Patterns often say "increase 6 stitches evenly across" without saying where. Guessing makes lumpy, lopsided shaping. This calculator writes out exactly where each increase or decrease goes, for rounds or rows, in US or UK terms, and checks that the stitches add up.

How to use the calculator

  1. Enter the stitches you have now and the stitches you want at the end. More means increase; fewer means decrease.
  2. Choose in the round or in rows. Rows keep the shaping away from the edges where there are enough plain stitches.
  3. Choose the stitch you are working.
  4. Follow the instruction line. The check table confirms the stitches used and made, and for up to 24 shaping points there is a checklist you can tick off.

How the calculator works

The current stitches are split into as many sections as there are increases or decreases, and each section ends with the shaping stitch.

Stitches per section = current stitches ÷ number of increases or decreases

An increase uses 1 stitch (2 stitches worked into one), so the plain stitches in a section are its size minus 1. A decrease uses 2 stitches (such as sc2tog), so the plain stitches are its size minus 2.

When the stitches do not divide evenly, some sections get one extra plain stitch. The longer sections are spread out evenly, using Bresenham's method from computer graphics, so they never bunch together. Repeating sections are then written as a repeat.

  • In the round the stitches form a loop, and the shortest repeating pattern is written as *…* rep N times.
  • In rows the first section's plain stitches are split between the start and the end of the row, so the shaping stays off the edge stitches. When each section has only one plain stitch, a row may start with the shaping stitch.

Reading your results

  • Instructions: the row or round written out in pattern style, ending with the new stitch count.
  • Check: stitches used from the row below and stitches made, so you can see it adds up.
  • Checklist: each section in order, for counting as you go.

Worked examples

  • 30 to 36 stitches in the round: 6 increases, 5 stitches per section: *4 sc, 2 sc in next st* rep 6 times. (36 sts)
  • 68 to 76 stitches in the round, half double crochet: 8 increases. 68 ÷ 8 = 8 remainder 4, so sections of 8 and 9 stitches alternate: *7 hdc, 2 hdc in next st, 8 hdc, 2 hdc in next st* rep 4 times. (76 sts)
  • 74 to 66 stitches in a row: 8 decreases. 74 ÷ 8 = 9 remainder 2, so six sections of 9 and two of 10. The first gap is split between the two ends: 3 sc, sc2tog, [7 sc, sc2tog] twice, 8 sc, sc2tog, [7 sc, sc2tog] 3 times, 8 sc, sc2tog, 4 sc. (66 sts)

US and UK terms

Switch the calculator to UK terms and every stitch name in the results changes; the numbers stay the same. UK names are one step taller than US names for the same stitch:

  • US single crochet (sc) = UK double crochet (dc)
  • US half double crochet (hdc) = UK half treble (htr)
  • US double crochet (dc) = UK treble (tr)
  • US treble (tr) = UK double treble (dtr)

A decrease written sc2tog in US terms is dc2tog in UK terms.

Accuracy and limits

  • The instructions are exact and covered by our automated tests, which work every combination of up to 120 stitches and check the counts.
  • At most one increase per stitch, which doubles the count. For more, work 3 stitches into some stitches or spread the increases over two rows or rounds.
  • Each decrease uses 2 stitches, so a row can lose at most half its stitches.

Common mistakes

  1. Using a knitting calculator. Many knitting increases are worked between stitches and use no stitch. In crochet every increase is worked into a stitch, so knitting spacing leaves you short at the end of the round.
  2. Losing count on uneven repeats. When the sections alternate between two sizes, place stitch markers where each shaping stitch goes before you start.

Tips for more accurate results

  • On amigurumi, an invisible decrease (through the front loops of the next two stitches) can replace sc2tog. The count is the same: 2 stitches used, 1 made.
  • In the round, start each round at a different point, or offset the first section, if you see the increases stacking into corners.

Frequently asked questions

Why are there fewer plain stitches between decreases than between increases?

An increase is worked into 1 stitch; a decrease uses 2. In a 5-stitch section, an increase leaves 4 plain stitches and a decrease leaves 3.

What is the difference between in the round and in rows?

In the round, the stitches form a loop and the instructions repeat all the way round. In rows, the first section's plain stitches are split between both ends, which keeps the shaping off the edge stitches whenever there are at least two of them.

How do I space increases when the numbers don't divide evenly?

Divide the stitches by the number of increases. The remainder tells you how many sections need one extra stitch. The calculator spreads those longer sections evenly for you.

Why can't I use a knitting increase calculator for crochet?

Knitting increases such as make 1 often use no stitch from the needle; crochet increases always use one. A knitting calculator leaves you one stitch short on each repeat.

What if I need to more than double, or more than halve, my stitches?

Work 3 stitches into some stitches, decrease 3 stitches together, or spread the shaping over two rows or rounds.

Related guides and tools

Questions about this calculator

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