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Sleeve Ease Calculator
Calculate sleeve cap ease based on armhole measurement and garment style.
How We Calculate This
Ease Calculation
Sleeve Cap Length = Armhole Measurement + Ease Amount
Base ease comes from garment style, is adjusted for fabric type, then nudged for cap height. A smoothly set-in cap on a woven holds roughly 3 to 5cm of ease — a fitted cap is typically 3 to 4.5cm (1¼ to 1¾"), so the automatic value is capped at 5cm. Anything beyond that has to be gathered or pleated into a puff sleeve.
Fabric Adjustment
Knit and stretch fabrics multiply the base ease by 0.4 to 0.6, reducing it because the fabric stretches into shape. Wool and denim multiply by 1.1 to 1.15, increasing it slightly.
Cap Height
Taller set-in caps need a little more ease; flatter or dropped-shoulder caps need less, because the dropped shoulder does the shaping. Around 15cm is treated as the neutral cap height.
Distribution
Most ease should be concentrated at the top of the sleeve cap, with decreasing amounts toward the underarm notches.
Frequently Asked Questions
Sleeve cap ease is the extra length in the sleeve cap seam compared to the armhole seam. This extra fabric is eased (gently gathered) into the armhole when sewing the sleeve in, creating a smooth, rounded cap shape that follows the shoulder contour.
For woven fabrics, 2.5 to 4cm is typical. Fitted garments use less ease (2 to 3cm), while tailored jackets may use 3 to 4cm. Stretch and knit fabrics need less ease (1 to 2cm) because the fabric stretches into shape.
Too much ease causes puckers and tucks at the sleeve cap that cannot be pressed flat. Too little ease produces a flat, lifeless sleeve cap that may pull or restrict arm movement. The right amount creates a smooth, rounded shape.
Sew two long basting rows between the notches at the top of the cap so they straddle the seam line — for a 1.5cm (5/8") seam allowance, run one row about 1.3cm from the raw edge (just inside the seam line, within the seam allowance) and the other about 1.7cm from the edge (just past the seam line into the garment body). Gently pull the bobbin threads to draw up the ease, then pin the sleeve into the armhole matching notches. Stitch the final seam at 1.5cm, running between the two basting rows, and press over a tailor ham.
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Last updated: March 2026
All calculations are estimates. Always verify quantities before cutting or purchasing fabric.