Sleeve Cap Calculator
A starting framework for set-in sleeve cap decreases and bind-offs.
Result
Bind off 3 sts at the start of the next 2 rows, then decrease 1 st at each end every 2nd row, 9 times, then every row, 9 times. Bind off the remaining 18 sts across the top. Cap decreases fall on both right-side and wrong-side rows — normal for a cap, and different from the armhole, where every decrease row is a right-side row.
3 off each underarm · 18 decreased each side · 18 off the top.
A starting framework, not a full fitted cap curve. Set the cap into the armhole and adjust the pace of the decreases so it eases in without puckering.
Calculated at fibercalc.site/sleeve-cap — free knitting & crochet calculators.
How to use
- Enter the sleeve width at the underarm in stitches (the full sleeve width where the cap begins).
- Enter the cap height in rows — usually close to the body armhole depth.
- Enter the underarm bind-off, matching the stitches you bound off at the body armhole so the seams meet.
- Read the framework: bind off the underarm, decrease up the cap — spaced wider at first, then closer together towards the top — and bind off the top.
Good to know
- The sleeve cap is the fiddliest piece of sweater shaping. This gives a two-rate starting point — the decreases are spaced wider low on the cap and closer together towards the top — not a full three-zone cap curve. The exact curve is fine-tuned by easing the cap into the armhole so it sits smoothly.
- Match the underarm bind-off to the body armhole so the underarm seams line up.
- If the cap will not ease in smoothly, move the changeover between the two rates: shift decreases towards the top for a narrower cap, towards the bottom for a wider one. The number of decreases stays the same — only the shape of the cap edge changes.
- A starting framework, not a full fitted cap curve — set the cap into the armhole and adjust the pace of the decreases so it eases in without puckering.
- Worked example: a 72-stitch sleeve with a 40-row cap and a 4-stitch underarm bind-off decreases 21 stitches each side — every 2nd row 16 times, then every row 5 times — before binding off the remaining 22 stitches at the top.
FAQ
- How tall should the cap be?
- Roughly the same as the body armhole depth, sometimes a little less. The cap has to ease into the armhole, so its edge is slightly longer than the armhole edge.
- Why is the sleeve cap so hard?
- It is a curve that has to fit another curve (the armhole) with a little ease, so the decrease rate changes along the cap. This calculator gives a two-rate framework that speeds up towards the top; the final fit is adjusted as you set it in.
- Is this a full sleeve cap pattern?
- It is a planning framework — the underarm bind-off, the number of decreases, and a two-step spacing that tightens towards the top. Traditional caps vary the decrease rate in three zones along the cap; use this as a starting point and adjust to your armhole.