The armscye (also called armhole) is the opening in a garment where the sleeve attaches. It is the curved seam line around the shoulder and underarm. The armscye circumference determines how the sleeve fits into the bodice.

How do I measure armhole circumference?

Measure around the armhole seam line on the garment (or pattern). Include front and back armhole lengths. Alternatively, estimate from body measurements: bicep circumference plus ease plus 8cm works for a basic set-in sleeve.

What is sleeve cap ease?

Sleeve cap ease is the extra length in the sleeve cap seam line over the armhole seam line, which is distributed evenly so the sleeve sits smoothly over the rounded shoulder. For woven set-in sleeves it is roughly 6-10% of the armhole circumference (around 2.5-4.5cm on an average armhole). This calculator works it out as a percentage of the armhole circumference, which you can adjust under Advanced Options.

How do I adjust the armhole depth?

A common drafting guideline for women is armhole depth = bust circumference ÷ 6 + 1.5 inch (3.8cm), which gives about 19cm for a 90cm (36 inch) bust. Raise the armhole (less depth) for a fitted, active garment. Lower it for comfort and ease of movement.

SewCalcs

Armscye Calculator — Armhole Circumference

Calculate armscye (armhole) circumference and adjustments.

Bust Circumference

Full bust circumference, sets armhole depth

Bicep Circumference

Around the widest part of the upper arm

Ease

Wearing ease over the bicep; 3-5cm for a standard fit

How We Calculate This

Armhole (scye) circumference is estimated from the bicep measurement plus wearing ease plus an underarm-curve allowance. Armhole depth is derived from the bust circumference. Sleeve cap height and cap ease are both worked out from the armhole circumference.

The formula

Armhole circ ≈ Bicep + Ease + 8cm

Armhole depth ≈ Bust circ ÷ 6 + 3.8cm (= Bust ÷ 6 + 1.5 inch)

Sleeve cap height ≈ Armhole circ ÷ 3 (fitted set-in sleeve)

Sleeve cap ease ≈ Armhole circ × ease % (woven 6–10%)

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.