How Many Stitches to Cast on for a Cardigan?

At a 40.5-inch finished chest circumference and 4.5 stitches per inch (this site's adult-average sweater example), the raw math gives 182 stitches, rounding down to 180 for a clean hem-rib multiple of 4 — see the adult-average sweater page for the full working.

Why a cardigan's cast-on isn't quite the same question as a pullover's

The chest-to-stitch-count math itself is identical to a pullover's — see the adult sweater size chart for the shared chest bands both use. What's different is what happens to that total count structurally: a cardigan worked flat (not in the round) needs its cast-on split by the front opening, with steek-free construction typically working the two fronts and back as separate flat pieces, or as one piece with a center-front split marked but not physically separated until later.

Front bands aren't part of this number

The cast-on total above covers the body only — a cardigan's front button bands are picked up and worked afterward, using the row-gauge-to-stitch-gauge ratio covered on the picking up stitches page, not folded into the initial cast-on count.

Getting your own number

For a different size or gauge, plug your own chest measurement, chosen ease, and real gauge directly into the Cast-On Calculator rather than scaling the 180-stitch example above by eye — chest circumference and ease both shift this total directly.

FAQ

Does a cardigan need more cast-on stitches than a pullover at the identical chest size? No — the body cast-on itself is identical; the cardigan's extra stitches come later, from the front bands worked separately, not from a bigger initial cast-on.

Is the cast-on worked flat or in the round for a cardigan? Almost always flat, given the front opening — a cardigan generally can't be worked in the round the way a pullover sometimes is, since the open front interrupts the circular structure a round construction relies on.

Does ease change this number as much as chest size does? Yes, meaningfully — the ease guide breaks down real inch ranges by intended fit, and a cardigan carrying more positive ease than this example's assumed amount needs a correspondingly higher stitch count at the identical chest measurement.

Should the two front pieces and the back use the same cast-on multiple? Not necessarily the identical multiple, since each piece's own edge stitch pattern (a button band's edge treatment versus a side seam) can call for its own rounding — check each piece's stitch pattern individually rather than assuming one shared multiple covers all three.