Cast On Calculator
Stitches to cast on for a target width.
Calculate how many stitches to cast on for a width at your gauge, rounded to a stitch pattern repeat with edge stitches.
A "multiple of 4 plus 2" pattern: enter 4 here and 2 below.
Cast on
110
20.00" at 5.50 sts/in
The cast-on method matters as much as the count for anything that has to stretch. A long-tail cast-on is firm and a cable cast-on firmer; for a ribbed hem going over hips, a stretchy or tubular cast-on is worth more than a stitch either way.
How the Cast On Calculator works
Width times gauge gives the stitch count, and then the stitch pattern has an opinion about it. A rib over a multiple of four, a cable panel needing six plus two edge stitches — the cast-on has to be a valid count for the pattern, not just the nearest whole number, and rounding to the wrong side is what produces a garment half an inch out at every repeat.
Also known as: stitch count calculator · how many stitches calculator
How the number is derived
Width times gauge gives the raw stitch count, and then the stitch pattern constrains it. A pattern that repeats over four stitches with two extra to balance the ends can only be worked over counts of the form 4n+2, so the raw figure has to be rounded to the nearest valid one.
That rounding is where a calculator earns its place. Rounding 110 to the nearest multiple of six plus three gives 111, which is a stitch and a bit wider than intended — fine. Rounding to the nearest multiple of twelve could move it by six stitches, which is over an inch at most gauges.
The wider the repeat, the more the rounding matters, which is why cable and lace patterns often list a separate stitch count per size rather than a formula.
A worked example
Twenty inches at 5.5 stitches per inch is 110 stitches. Over a six-stitch repeat with three edge stitches, the valid counts are 105, 111 and 117. The nearest is 111, which measures 20.2 inches — two tenths over, invisible in wear.
Had the repeat been sixteen stitches, the options would be 99 and 115: 18 inches or 20.9. Neither is 20, and at that point the honest move is to adjust the design rather than the count — dropping an edge stitch or adding a narrow panel is easier than living with an inch of error.
Where the answer misleads
Ribbing does not measure the same as the fabric above it. A 2×2 rib pulls in substantially, so a hem cast on at the body's stitch count will be much narrower than the body — which is usually wanted, but means the cast-on count cannot be checked by measuring the hem.
The cast-on method changes the edge's stretch far more than a stitch either way changes the width. A long-tail cast-on is firm and a cable cast-on firmer still; for a hem that has to go over hips, a tubular or stretchy cast-on matters more than the count.
And gauge in ribbing differs from gauge in stocking stitch, so a cast-on calculated from a stocking stitch swatch is only right for the stocking stitch part of the garment.
Frequently asked questions
How many stitches should I cast on?
Multiply the width you want by your stitches per inch. Twenty inches at 5.5 stitches per inch is 110. Then round to whatever multiple your stitch pattern needs, plus any edge stitches it calls for.
What does 'multiple of 4 plus 2' mean?
The stitch pattern repeats every four stitches, and needs two extra to balance the ends. Valid counts are 4n+2: 42, 46, 50 and so on. Casting on 44 will leave the pattern off-centre or incomplete at one edge.
Should I round up or down?
Toward whichever is closer, unless the fabric is very stretchy or the fit is critical. For ribbing that pulls in, rounding down is usually safe; for a flat stitch at a fixed width, take the nearer count and adjust with blocking.
Does the cast-on method change the count?
Not the count, but it changes the edge's stretch a great deal. A long-tail cast-on is firm and a cable cast-on firmer still; for a ribbed hem that needs to stretch over hips, a tubular or stretchy cast-on matters more than a stitch either way.